Hi all,
The v3 of this patch addresses feedback I received on the version posted at [1].
The merged store buffer is now represented as a char array that we splat values
onto with
native_encode_expr and native_interpret_expr. This allows us to merge anything
that native_encode_expr
accepts, including floating point values and short vectors. So this version
extends the functionality
of the previous one in that it handles floating point values as well.
The first phase of the algorithm that detects the contiguous stores is also
slightly refactored according
to feedback to read more fluently.
Richi, I experimented with merging up to MOVE_MAX bytes rather than word size
but I got worse results on aarch64.
MOVE_MAX there is 16 (because it has load/store register pair instructions) but
the 128-bit immediates that we ended
synthesising were too complex. Perhaps the TImode immediate store RTL
expansions could be improved, but for now
I've left the maximum merge size to be BITS_PER_WORD.
I've disabled the pass for PDP-endian targets as the merging code proved to be
quite fiddly to get right for different
endiannesses and I didn't feel comfortable writing logic for BYTES_BIG_ENDIAN
!= WORDS_BIG_ENDIAN targets without serious
testing capabilities. I hope that's ok (I note the bswap pass also doesn't try
to do anything on such targets).
Tested on arm, aarch64, x86_64 and on big-endian arm and aarch64.
How does this version look?
Thanks,
Kyrill
[1] https://gcc.gnu.org/ml/gcc-patches/2016-08/msg01512.html
2016-09-06 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
PR middle-end/22141
* Makefile.in (OBJS): Add gimple-ssa-store-merging.o.
* common.opt (fstore-merging): New Optimization option.
* opts.c (default_options_table): Add entry for
OPT_ftree_store_merging.
* params.def (PARAM_STORE_MERGING_ALLOW_UNALIGNED): Define.
* passes.def: Insert pass_tree_store_merging.
* tree-pass.h (make_pass_store_merging): Declare extern
prototype.
* gimple-ssa-store-merging.c: New file.
* doc/invoke.texi (Optimization Options): Document
-fstore-merging.
2016-09-06 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
Jakub Jelinek <ja...@redhat.com>
PR middle-end/22141
* gcc.c-torture/execute/pr22141-1.c: New test.
* gcc.c-torture/execute/pr22141-2.c: Likewise.
* gcc.target/aarch64/ldp_stp_1.c: Adjust for -fstore-merging.
* gcc.target/aarch64/ldp_stp_4.c: Likewise.
* gcc.dg/store_merging_1.c: New test.
* gcc.dg/store_merging_2.c: Likewise.
* gcc.dg/store_merging_3.c: Likewise.
* gcc.dg/store_merging_4.c: Likewise.
* gcc.dg/store_merging_5.c: Likewise.
* gcc.dg/store_merging_6.c: Likewise.
* gcc.target/i386/pr22141.c: Likewise.
* gcc.target/i386/pr34012.c: Add -fno-store-merging to dg-options.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 5e3cbe5d736e2cf9429df989d9d95708b1243011..ca2415b79de60c9be44871777d57bcc8d5c07487 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1295,6 +1295,7 @@ OBJS = \
gimple-ssa-isolate-paths.o \
gimple-ssa-nonnull-compare.o \
gimple-ssa-split-paths.o \
+ gimple-ssa-store-merging.o \
gimple-ssa-strength-reduction.o \
gimple-streamer-in.o \
gimple-streamer-out.o \
diff --git a/gcc/common.opt b/gcc/common.opt
index 2004fbc7d0d7b1ca65d06cee0f7398f2c9e3fc64..d951ae7cd6fe8fdae17e17b8f5be7c636ea1986d 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1452,6 +1452,10 @@ fstrict-volatile-bitfields
Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
Force bitfield accesses to match their type width.
+fstore-merging
+Common Var(flag_store_merging) Optimization
+Use the tree store merging pass.
+
fguess-branch-probability
Common Report Var(flag_guess_branch_prob) Optimization
Enable guessing of branch probabilities.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 87da1f1c12b718fa63c9b89fdd8f85fbc6b54cb0..2e2a9fdd92733beb6948efc7a5c4b3fc79da73a9 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -401,7 +401,7 @@ Objective-C and Objective-C++ Dialects}.
-fsingle-precision-constant -fsplit-ivs-in-unroller @gol
-fsplit-paths @gol
-fsplit-wide-types -fssa-backprop -fssa-phiopt @gol
--fstdarg-opt -fstrict-aliasing @gol
+-fstdarg-opt -fstore-merging -fstrict-aliasing @gol
-fstrict-overflow -fthread-jumps -ftracer -ftree-bit-ccp @gol
-ftree-builtin-call-dce -ftree-ccp -ftree-ch @gol
-ftree-coalesce-vars -ftree-copy-prop -ftree-dce -ftree-dominator-opts @gol
@@ -412,8 +412,8 @@ Objective-C and Objective-C++ Dialects}.
-ftree-loop-vectorize @gol
-ftree-parallelize-loops=@var{n} -ftree-pre -ftree-partial-pre -ftree-pta @gol
-ftree-reassoc -ftree-sink -ftree-slsr -ftree-sra @gol
--ftree-switch-conversion -ftree-tail-merge -ftree-ter @gol
--ftree-vectorize -ftree-vrp -funconstrained-commons @gol
+-ftree-switch-conversion -ftree-tail-merge @gol
+-ftree-ter -ftree-vectorize -ftree-vrp -funconstrained-commons @gol
-funit-at-a-time -funroll-all-loops -funroll-loops @gol
-funsafe-math-optimizations -funswitch-loops @gol
-fipa-ra -fvariable-expansion-in-unroller -fvect-cost-model -fvpt @gol
@@ -6339,6 +6339,7 @@ compilation time.
-fsplit-wide-types @gol
-fssa-backprop @gol
-fssa-phiopt @gol
+-fstore-merging @gol
-ftree-bit-ccp @gol
-ftree-ccp @gol
-ftree-ch @gol
@@ -7673,6 +7674,13 @@ Perform scalar replacement of aggregates. This pass replaces structure
references with scalars to prevent committing structures to memory too
early. This flag is enabled by default at @option{-O} and higher.
+@item -fstore-merging
+@opindex fstore-merging
+Perform merging of narrow stores to consecutive memory addresses. This pass
+merges contigous stores of immediate values narrower than a word into fewer
+wider stores to reduce the number of instructions. This is enabled by default
+at @option{-O} and higher.
+
@item -ftree-ter
@opindex ftree-ter
Perform temporary expression replacement during the SSA->normal phase. Single
diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c
new file mode 100644
index 0000000000000000000000000000000000000000..36e2e2a1e6bae3992c3ce84edbb5067dfa504f02
--- /dev/null
+++ b/gcc/gimple-ssa-store-merging.c
@@ -0,0 +1,1038 @@
+/* GIMPLE store merging pass.
+ Copyright (C) 2016 Free Software Foundation, Inc.
+ Contributed by ARM Ltd.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ GCC is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GCC; see the file COPYING3. If not see
+ <http://www.gnu.org/licenses/>. */
+
+/* The purpose of this pass is to combine multiple memory stores of
+ constant values to consecutive memory locations into fewer wider stores.
+ For example, if we have a sequence peforming four byte stores to
+ consecutive memory locations:
+ [p ] := imm1;
+ [p + 1B] := imm2;
+ [p + 2B] := imm3;
+ [p + 3B] := imm4;
+ we can transform this into a single 4-byte store if the target supports it:
+ [p] := imm1:imm2:imm3:imm4 //concatenated immediates according to endianness.
+
+ The algorithm is applied to each basic block in three phases:
+
+ 1) Scan through the basic block recording constant assignments to
+ destinations that can be expressed as a store to memory of a certain size
+ at a certain bit offset. Record store chains to different bases in a
+ hash_map (m_stores) and make sure to terminate such chains when appropriate
+ (for example when when the stored values get used subsequently).
+ These stores can be a result of structure element initializers, array stores
+ etc. A store_immediate_info object is recorded for every such store.
+ Record as many such assignments to a single base as possible until a
+ statement that interferes with the store sequence is encountered.
+
+ 2) Analyze the chain of stores recorded in phase 1) (i.e. the vector of
+ store_immediate_info objects) and coalesce contiguous stores into
+ merged_store_group objects.
+
+ For example, given the stores:
+ [p ] := 0;
+ [p + 1B] := 1;
+ [p + 3B] := 0;
+ [p + 4B] := 1;
+ [p + 5B] := 0;
+ [p + 6B] := 0;
+ This phase would produce two merged_store_group objects, one recording the
+ two bytes stored in the memory region [p : p + 1] and another
+ recording the four bytes stored in the memory region [p + 3 : p + 6].
+
+ 3) The merged_store_group objects produced in phase 2) are processed
+ to generate the sequence of wider stores that set the contiguous memory
+ regions to the sequence of bytes that correspond to it. This may emit
+ multiple stores per store group to handle contiguous stores that are not
+ of a size that is a power of 2. For example it can try to emit a 40-bit
+ store as a 32-bit store followed by an 8-bit store.
+ We try to emit as wide stores as we can while respecting STRICT_ALIGNMENT or
+ SLOW_UNALIGNED_ACCESS rules.
+
+ Note on endianness and example:
+ Consider 2 contiguous 16-bit stores followed by 2 contiguous 8-bit stores:
+ [p ] := 0x1234;
+ [p + 2B] := 0x5678;
+ [p + 4B] := 0xab;
+ [p + 5B] := 0xcd;
+
+ The memory layout for little-endian (LE) and big-endian (BE) must be:
+ p |LE|BE|
+ ---------
+ 0 |34|12|
+ 1 |12|34|
+ 2 |78|56|
+ 3 |56|78|
+ 4 |ab|ab|
+ 5 |cd|cd|
+
+ To merge these into a single 48-bit merged value 'val' in phase 2)
+ on little-endian we insert stores to higher (consecutive) bitpositions
+ into the most significant bits of the merged value.
+ The final merged value would be: 0xcdab56781234
+
+ For big-endian we insert stores to higher bitpositions into the least
+ significant bits of the merged value.
+ The final merged value would be: 0x12345678abcd
+
+ Then, in phase 3), we want to emit this 48-bit value as a 32-bit store
+ followed by a 16-bit store. Again, we must consider endianness when
+ breaking down the 48-bit value 'val' computed above.
+ For little endian we emit:
+ [p] (32-bit) := 0x56781234; // val & 0x0000ffffffff;
+ [p + 4B] (16-bit) := 0xcdab; // (val & 0xffff00000000) >> 32;
+
+ Whereas for big-endian we emit:
+ [p] (32-bit) := 0x12345678; // (val & 0xffffffff0000) >> 16;
+ [p + 4B] (16-bit) := 0xabcd; // val & 0x00000000ffff; */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "backend.h"
+#include "tree.h"
+#include "gimple.h"
+#include "builtins.h"
+#include "fold-const.h"
+#include "tree-pass.h"
+#include "ssa.h"
+#include "gimple-pretty-print.h"
+#include "alias.h"
+#include "fold-const.h"
+#include "params.h"
+#include "print-tree.h"
+#include "tree-hash-traits.h"
+#include "gimple-iterator.h"
+#include "gimplify.h"
+#include "target.h"
+
+/* The maximum size (in bits) of the stores this pass should generate. */
+#define MAX_STORE_BITSIZE (BITS_PER_WORD)
+#define MAX_STORE_BYTES (MAX_STORE_BITSIZE / BITS_PER_UNIT)
+
+namespace {
+
+/* Struct recording the information about a single store of an immediate
+ to memory. These are created in the first phase and coalesced into
+ merged_store_group objects in the second phase. */
+
+struct store_immediate_info
+{
+ HOST_WIDE_INT bitsize;
+ HOST_WIDE_INT bitpos;
+ tree val;
+ tree dest;
+ gimple *stmt;
+ unsigned int order;
+ store_immediate_info (HOST_WIDE_INT, HOST_WIDE_INT, tree, tree, gimple *,
+ unsigned int);
+};
+
+store_immediate_info::store_immediate_info (HOST_WIDE_INT bs, HOST_WIDE_INT bp,
+ tree v, tree d, gimple *st,
+ unsigned int ord)
+ : bitsize (bs), bitpos (bp), val (v), dest (d), stmt (st), order (ord)
+{
+}
+
+/* Struct representing a group of stores to contiguous memory locations.
+ These are produced by the second phase (coalescing) and consumed in the
+ third phase that outputs the widened stores. */
+
+struct merged_store_group
+{
+ HOST_WIDE_INT start;
+ HOST_WIDE_INT width;
+ unsigned char *val;
+ unsigned int align;
+ auto_vec<struct store_immediate_info *> stores;
+ /* We record the first and last original statements in the sequence because
+ because we'll need their vuse/vdef and replacement position. */
+ gimple *last_stmt;
+ unsigned int last_order;
+
+ gimple *first_stmt;
+ unsigned int first_order;
+ merged_store_group (store_immediate_info *);
+ ~merged_store_group ();
+ void merge_into (store_immediate_info *);
+ void merge_overlapping (store_immediate_info *);
+ void apply_stores ();
+};
+
+/* Debug helper. Dump LEN elements of byte array PTR to FD in hex. */
+
+static void
+dump_char_array (FILE *fd, unsigned char *ptr, unsigned int len)
+{
+ if (!fd)
+ return;
+
+ for (unsigned int i = 0; i < len; i++)
+ fprintf (fd, "%x ", ptr[i]);
+ fprintf (fd, "\n");
+}
+
+/* Write BITLEN bits of EXPR to the byte array PTR at
+ bit position BITPOS. PTR should contain MAX_STORE_BYTES elements. */
+
+static void
+encode_tree_to_bitpos (tree expr, unsigned char *ptr, int bitlen, int bitpos)
+{
+ unsigned char *tmpbuf = XALLOCAVEC (unsigned char, MAX_STORE_BYTES);
+ memset (tmpbuf, 0, MAX_STORE_BYTES);
+ int last_byte = (bitpos + bitlen) / BITS_PER_UNIT;
+ gcc_assert (last_byte <= MAX_STORE_BYTES);
+ native_encode_expr (expr, tmpbuf, MAX_STORE_BYTES, 0);
+ tree read_back_type
+ = build_nonstandard_integer_type (TYPE_PRECISION (TREE_TYPE (expr)),
+ UNSIGNED);
+ tree tmp_int
+ = native_interpret_expr (read_back_type, tmpbuf, MAX_STORE_BYTES);
+
+ gcc_assert (tmp_int);
+
+ tree dest_int_type
+ = build_nonstandard_integer_type (MAX_STORE_BITSIZE, UNSIGNED);
+ tree ptr_wide_int
+ = native_interpret_expr (dest_int_type, ptr, MAX_STORE_BYTES);
+ wide_int dest_wide_int
+ = wi::to_wide (ptr_wide_int, TYPE_PRECISION (dest_int_type));
+ wide_int expr_wide_int = wi::to_wide (tmp_int, MAX_STORE_BITSIZE);
+ if (BYTES_BIG_ENDIAN)
+ dest_wide_int = wi::insert (dest_wide_int, expr_wide_int,
+ MAX_STORE_BITSIZE - bitlen - bitpos, bitlen);
+ else
+ dest_wide_int = wi::insert (dest_wide_int, expr_wide_int, bitpos, bitlen);
+
+ tree res = wide_int_to_tree (dest_int_type, dest_wide_int);
+
+ native_encode_expr (res, ptr, MAX_STORE_BYTES, 0);
+}
+
+/* Sorting function for store_immediate_info objects.
+ Sorts them by bitposition. */
+
+static int
+sort_by_bitpos (const void *x, const void *y)
+{
+ store_immediate_info *const *tmp = (store_immediate_info * const *) x;
+ store_immediate_info *const *tmp2 = (store_immediate_info * const *) y;
+
+ if ((*tmp)->bitpos <= (*tmp2)->bitpos)
+ return -1;
+ else if ((*tmp)->bitpos > (*tmp2)->bitpos)
+ return 1;
+
+ gcc_unreachable ();
+ return 0;
+}
+
+/* Sorting function for store_immediate_info objects.
+ Sorts them by the order field. */
+
+static int
+sort_by_order (const void *x, const void *y)
+{
+ store_immediate_info *const *tmp = (store_immediate_info * const *) x;
+ store_immediate_info *const *tmp2 = (store_immediate_info * const *) y;
+
+ if ((*tmp)->order < (*tmp2)->order)
+ return -1;
+ else if ((*tmp)->order > (*tmp2)->order)
+ return 1;
+
+ gcc_unreachable ();
+ return 0;
+}
+
+/* Initialize a merged_store_group object from a store_immediate_info
+ object. */
+
+merged_store_group::merged_store_group (store_immediate_info *info)
+{
+ start = info->bitpos;
+ width = info->bitsize;
+ val = new unsigned char[MAX_STORE_BYTES];
+ align = get_object_alignment (info->dest);
+ stores.create (1);
+ stores.safe_push (info);
+ last_stmt = info->stmt;
+ last_order = info->order;
+ first_stmt = last_stmt;
+ first_order = last_order;
+}
+
+merged_store_group::~merged_store_group ()
+{
+ delete[] val;
+}
+
+/* Merge a store recorded by INFO into this merged store.
+ The store is not overlapping with the existing recorded
+ stores. */
+
+void
+merged_store_group::merge_into (store_immediate_info *info)
+{
+ HOST_WIDE_INT wid = info->bitsize;
+ /* Make sure we're inserting in the position we think we're inserting. */
+ gcc_assert (info->bitpos == start + width);
+
+ width += wid;
+ gimple *stmt = info->stmt;
+ stores.safe_push (info);
+ if (info->order > last_order)
+ {
+ last_order = info->order;
+ last_stmt = stmt;
+ }
+ else if (info->order < first_order)
+ {
+ first_order = info->order;
+ first_stmt = stmt;
+ }
+}
+
+/* Merge a store described by INFO into this merged store.
+ INFO overlaps in some way with the current store (i.e. it's not contiguous
+ which is handled by merged_store_group::merge_into). */
+
+void
+merged_store_group::merge_overlapping (store_immediate_info *info)
+{
+ gimple *stmt = info->stmt;
+ stores.safe_push (info);
+
+ /* If the store extends the size of the group, extend the width. */
+ if ((info->bitpos + info->bitsize) > (start + width))
+ width += info->bitpos + info->bitsize - (start + width);
+
+ if (info->order > last_order)
+ {
+ last_order = info->order;
+ last_stmt = stmt;
+ }
+ else if (info->order < first_order)
+ {
+ first_order = info->order;
+ first_stmt = stmt;
+ }
+}
+
+/* Go through all the recorded stores in this group in program order and
+ apply their values to the VAL byte array to create the final merged
+ value. */
+
+void
+merged_store_group::apply_stores ()
+{
+ stores.qsort (sort_by_order);
+ struct store_immediate_info *info;
+ unsigned int i;
+ memset (val, 0, MAX_STORE_BYTES);
+
+ FOR_EACH_VEC_ELT (stores, i, info)
+ {
+ unsigned int pos_in_buffer = info->bitpos - start;
+ encode_tree_to_bitpos (info->val, val, info->bitsize, pos_in_buffer);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Afer writing ");
+ print_generic_expr (dump_file, info->val, 0);
+ fprintf (dump_file, " at position %d the merged region contains:\n",
+ pos_in_buffer);
+ dump_char_array (dump_file, val, MAX_STORE_BYTES);
+ }
+ }
+}
+
+/* Structure describing the store chain. */
+
+struct imm_store_chain_info
+{
+ auto_vec<struct store_immediate_info *> m_store_info;
+ auto_vec<merged_store_group *> m_merged_store_groups;
+
+ bool terminate_and_process_chain (tree);
+ bool coalesce_immediate_stores ();
+ bool output_merged_store (tree, merged_store_group *);
+ bool output_merged_stores (tree);
+};
+
+const pass_data pass_data_tree_store_merging = {
+ GIMPLE_PASS, /* type */
+ "store-merging", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_NONE, /* tv_id */
+ PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_update_ssa, /* todo_flags_finish */
+};
+
+class pass_store_merging : public gimple_opt_pass
+{
+public:
+ pass_store_merging (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_tree_store_merging, ctxt)
+ {
+ }
+
+ /* Pass not supported for PDP-endianness. */
+ virtual bool
+ gate (function *)
+ {
+ return flag_store_merging && optimize
+ && (WORDS_BIG_ENDIAN == BYTES_BIG_ENDIAN);
+ }
+
+ virtual unsigned int execute (function *);
+
+private:
+ hash_map<tree_operand_hash, struct imm_store_chain_info *> m_stores;
+
+ bool terminate_and_process_all_chains ();
+ bool terminate_all_aliasing_chains (tree, tree, gimple *);
+ bool terminate_and_release_chain (tree);
+}; // class pass_store_merging
+
+/* Terminate and process all recorded chains. Return true if any changes
+ were made. */
+
+bool
+pass_store_merging::terminate_and_process_all_chains ()
+{
+ hash_map<tree_operand_hash, struct imm_store_chain_info *>::iterator iter
+ = m_stores.begin ();
+ bool ret = false;
+ for (; iter != m_stores.end (); ++iter)
+ ret |= terminate_and_release_chain ((*iter).first);
+
+ return ret;
+}
+
+/* Terminate all chains that are affected by the assignment to DEST, appearing
+ in statement STMT and ultimately points to the object BASE. Return true if
+ at least one aliasing chain was terminated. BASE and DEST are allowed to
+ be NULL_TREE. In that case the aliasing checks are performed on the whole
+ statement rather than a particular operand in it. */
+
+bool
+pass_store_merging::terminate_all_aliasing_chains (tree dest, tree base,
+ gimple *stmt)
+{
+ bool ret = false;
+
+ /* If the statement doesn't touch memory it can't alias. */
+ if (!gimple_vuse (stmt))
+ return false;
+
+ struct imm_store_chain_info **chain_info = NULL;
+
+ if (base)
+ {
+ chain_info = m_stores.get (base);
+ if (chain_info)
+ {
+ struct store_immediate_info *info;
+ unsigned int i;
+ FOR_EACH_VEC_ELT ((*chain_info)->m_store_info, i, info)
+ {
+ if (refs_may_alias_p (info->dest, dest))
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "stmt causes chain termination:\n");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
+ terminate_and_release_chain (base);
+ ret = true;
+ break;
+ }
+ }
+ }
+ }
+
+ hash_map<tree_operand_hash, struct imm_store_chain_info *>::iterator iter
+ = m_stores.begin ();
+
+ for (; iter != m_stores.end (); ++iter)
+ {
+ if (chain_info && (*chain_info) == (*iter).second)
+ continue;
+
+ tree key = (*iter).first;
+ if (ref_maybe_used_by_stmt_p (stmt, key)
+ || stmt_may_clobber_ref_p (stmt, key))
+ {
+ terminate_and_release_chain (key);
+ ret = true;
+ }
+ }
+
+ return ret;
+}
+
+/* Helper function. Terminate the recorded chain storing to base object
+ BASE. Return true if the merging and output was successful. The m_stores
+ entry is removed after the processing in any case. */
+
+bool
+pass_store_merging::terminate_and_release_chain (tree base)
+{
+ struct imm_store_chain_info **chain_info = m_stores.get (base);
+
+ if (!chain_info)
+ return false;
+
+ gcc_assert (*chain_info);
+
+ bool ret = (*chain_info)->terminate_and_process_chain (base);
+ delete *chain_info;
+ m_stores.remove (base);
+
+ return ret;
+}
+
+/* Go through the candidate stores recorded in m_store_info and merge them
+ into merged_store_group objects recorded into m_merged_store_groups
+ representing the widened stores. Return true if coalescing was successful
+ and the number of widened stores is fewer than the original number
+ of stores. */
+
+bool
+imm_store_chain_info::coalesce_immediate_stores ()
+{
+ /* Anything less can't be processed. */
+ if (m_store_info.length () < 2)
+ return false;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Attempting to coalesce %u stores in chain.\n",
+ m_store_info.length ());
+
+ store_immediate_info *info;
+ unsigned int i;
+
+ /* Order the stores by the bitposition they write to. */
+ m_store_info.qsort (sort_by_bitpos);
+
+ info = m_store_info[0];
+ merged_store_group *merged_store = new merged_store_group (info);
+ m_merged_store_groups.safe_push (merged_store);
+
+ FOR_EACH_VEC_ELT (m_store_info, i, info)
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "Store %u:\nbitsize:" HOST_WIDE_INT_PRINT_DEC
+ " bitpos:" HOST_WIDE_INT_PRINT_DEC " val:\n",
+ i, info->bitsize, info->bitpos);
+ print_generic_expr (dump_file, info->val, 0);
+ fprintf (dump_file, "\n------------\n");
+ }
+
+ if (i == 0)
+ continue;
+
+ unsigned int prev_size = merged_store->width;
+
+ /* |---store 1---|
+ |---store 2---|
+ Partially overlapping stores are not handled at the moment. */
+ HOST_WIDE_INT start = info->bitpos;
+ if (IN_RANGE (start, merged_store->start,
+ merged_store->start + merged_store->width - 1))
+ {
+ if (start + info->bitsize - merged_store->start > MAX_STORE_BITSIZE)
+ return false;
+
+ merged_store->merge_overlapping (info);
+ continue;
+ }
+
+ /* |---store 1---| <gap> |---store 2---|.
+ Gap between stores. Start a new group. */
+ if (start != merged_store->start + merged_store->width)
+ {
+ merged_store = new merged_store_group (info);
+ m_merged_store_groups.safe_push (merged_store);
+ continue;
+ }
+
+ /* |---store 1---||---store 2---|
+ This store is consecutive to the previous one. */
+
+ /* If we will be exceeding the maximum store size start a new group but
+ record the alignment of the new store appropriately. */
+ if (prev_size + info->bitsize > MAX_STORE_BITSIZE)
+ {
+ merged_store_group *new_merged_store = new merged_store_group (info);
+ new_merged_store->align
+ = MIN (merged_store->align, merged_store->width);
+ merged_store = new_merged_store;
+ m_merged_store_groups.safe_push (merged_store);
+ continue;
+ }
+ /* Merge it into the current store group. */
+ else
+ {
+ merged_store->merge_into (info);
+ continue;
+ }
+
+ gcc_unreachable ();
+ return false;
+ }
+
+ gcc_assert (m_merged_store_groups.length () <= m_store_info.length ());
+ bool success = m_merged_store_groups.length () < m_store_info.length ();
+ if (dump_file)
+ {
+ if (success)
+ fprintf (dump_file, "Coalescing successful!\n"
+ "Merged into %u stores\n",
+ m_merged_store_groups.length ());
+ }
+
+ if (success)
+ {
+ FOR_EACH_VEC_ELT (m_merged_store_groups, i, merged_store)
+ {
+ merged_store->apply_stores ();
+ }
+ }
+ return success;
+}
+
+/* Return the type to use for the merged stores described by GROUP.
+ This is needed to get the alias sets right. */
+
+static tree
+get_type_for_merged_store (merged_store_group *group)
+{
+ struct store_immediate_info *store;
+ unsigned int i;
+ tree lhs = gimple_assign_lhs (group->stores[0]->stmt);
+ tree type = reference_alias_ptr_type (lhs);
+ FOR_EACH_VEC_ELT (group->stores, i, store)
+ {
+ gimple *stmt = store->stmt;
+ if (i == 0)
+ continue;
+
+ lhs = gimple_assign_lhs (stmt);
+ tree type1 = reference_alias_ptr_type (lhs);
+ if (!alias_ptr_types_compatible_p (type, type1))
+ return ptr_type_node;
+ }
+ return type;
+}
+
+/* Return the location_t information we can find among the statements
+ in GROUP. */
+
+static location_t
+get_merged_store_location (merged_store_group *group)
+{
+ struct store_immediate_info *store;
+ unsigned int i;
+
+ FOR_EACH_VEC_ELT (group->stores, i, store)
+ {
+ gimple *stmt = store->stmt;
+ if (gimple_has_location (stmt))
+ return gimple_location (stmt);
+ }
+ return UNKNOWN_LOCATION;
+}
+
+/* Return true if storing an integer of bitsize SIZE using an unaligned
+ access if prohibitively slow. */
+
+static bool
+slow_unaligned_size_access (unsigned int size)
+{
+ machine_mode mode = mode_for_size (size, MODE_INT, 0);
+ gcc_assert (mode != BLKmode);
+ return SLOW_UNALIGNED_ACCESS (mode, GET_MODE_ALIGNMENT (mode));
+}
+
+/* Given a merged store group GROUP output the widened version of it.
+ The store chain is against the base object BASE.
+ Try store sizes of at most MAX_STORE_BITSIZE bits wide and don't output
+ unaligned stores for STRICT_ALIGNMENT targets or if it's too expensive.
+ Make sure that the number of statements output is less than the number of
+ original statements. If a better sequence is possible emit it and
+ return true. See note on endianness at top of file for an explanation of
+ the BYTES_BIG_ENDIAN logic. */
+
+bool
+imm_store_chain_info::output_merged_store (tree base, merged_store_group *group)
+{
+ HOST_WIDE_INT pos = group->start;
+ HOST_WIDE_INT size = group->width;
+ HOST_WIDE_INT bytepos = pos / BITS_PER_UNIT;
+ unsigned int align = group->align;
+ gcc_assert (IN_RANGE (size, 0, MAX_STORE_BITSIZE));
+
+ unsigned int orig_num_stmts = group->stores.length ();
+ if (orig_num_stmts < 2)
+ return false;
+
+ /* We don't handle partial bitfields for now. */
+ if ((size % BITS_PER_UNIT != 0) || (pos % BITS_PER_UNIT != 0))
+ return false;
+
+ bool allow_unaligned
+ = !STRICT_ALIGNMENT && PARAM_VALUE (PARAM_STORE_MERGING_ALLOW_UNALIGNED);
+ unsigned int try_size = MAX_STORE_BITSIZE;
+ while (try_size > size
+ || ((!allow_unaligned || slow_unaligned_size_access (try_size))
+ && try_size > align))
+ {
+ try_size /= 2;
+ if (try_size < BITS_PER_UNIT)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Failed to output merged store.\n"
+ "Failed to find starting size meeting"
+ " alignment requirements.\n");
+ }
+ return false;
+ }
+ }
+
+ HOST_WIDE_INT try_pos = bytepos;
+ int wi_offset = 0;
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "Trying to output merged store at pos " HOST_WIDE_INT_PRINT_DEC
+ ", of size " HOST_WIDE_INT_PRINT_DEC ", "
+ "starting size %u and alignment %u\n",
+ pos, size, try_size, align);
+ }
+
+ gimple_seq seq = NULL;
+ unsigned int num_stmts = 0;
+ tree offset_type = get_type_for_merged_store (group);
+ tree last_vdef, new_vuse;
+ last_vdef = gimple_vdef (group->last_stmt);
+ new_vuse = gimple_vuse (group->last_stmt);
+ location_t loc = get_merged_store_location (group);
+ gimple *stmt = NULL;
+ gimple_stmt_iterator last_gsi = gsi_for_stmt (group->last_stmt);
+
+ while (size > 0)
+ {
+ tree int_type = build_nonstandard_integer_type (try_size, UNSIGNED);
+ SET_TYPE_ALIGN (int_type, align);
+ tree addr = build_fold_addr_expr (base);
+ tree dest = fold_build2 (MEM_REF, int_type, addr,
+ build_int_cst (offset_type, try_pos));
+
+ tree src = native_interpret_expr (int_type,
+ group->val + wi_offset / BITS_PER_UNIT,
+ try_size / BITS_PER_UNIT);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Output src is:\n");
+ print_generic_expr (dump_file, src, 0);
+ fprintf (dump_file, "\n");
+ }
+ stmt = gimple_build_assign (dest, src);
+ gimple_set_vuse (stmt, new_vuse);
+ gimple_seq_add_stmt_without_update (&seq, stmt);
+ gimple_set_bb (stmt, gsi_bb (last_gsi));
+
+ num_stmts++;
+
+ try_pos += try_size / BITS_PER_UNIT;
+
+ wi_offset += try_size;
+ size -= try_size;
+ align = try_size;
+ while (size < try_size)
+ try_size /= 2;
+
+ if (num_stmts >= orig_num_stmts)
+ {
+ if (dump_file)
+ {
+ fprintf (dump_file, "Exceeded original number of stmts (%u)."
+ " Not profitable to emit new sequence.\n",
+ orig_num_stmts);
+ }
+ return false;
+ }
+
+ tree new_vdef
+ = size ? make_ssa_name (gimple_vop (cfun), stmt) : last_vdef;
+ gimple_set_vdef (stmt, new_vdef);
+ SSA_NAME_DEF_STMT (new_vdef) = stmt;
+ new_vuse = new_vdef;
+ }
+ gcc_assert (size == 0);
+ gcc_assert (seq);
+ annotate_all_with_location (seq, loc);
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "New sequence of %u stmts to replace old one of %u stmts\n",
+ num_stmts, orig_num_stmts);
+ if (dump_flags & TDF_DETAILS)
+ print_gimple_seq (dump_file, seq, 0, TDF_VOPS | TDF_MEMSYMS);
+ }
+ gsi_insert_seq_after (&last_gsi, seq, GSI_SAME_STMT);
+
+ return true;
+}
+
+/* Process the merged_store_group objects created in the coalescing phase.
+ The stores are all against the base object BASE.
+ Try to output the widened stores and delete the original statements if
+ successful. Return true iff any changes were made. */
+
+bool
+imm_store_chain_info::output_merged_stores (tree base)
+{
+ unsigned int i;
+ merged_store_group *merged_store;
+ bool ret = false;
+ FOR_EACH_VEC_ELT (m_merged_store_groups, i, merged_store)
+ {
+ bool successful_p = output_merged_store (base, merged_store);
+ if (successful_p)
+ {
+ unsigned int j;
+ store_immediate_info *store;
+ FOR_EACH_VEC_ELT (merged_store->stores, j, store)
+ {
+ gimple *stmt = store->stmt;
+ gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
+ gsi_remove (&gsi, true);
+ if (stmt != merged_store->last_stmt)
+ {
+ unlink_stmt_vdef (stmt);
+ release_defs (stmt);
+ }
+ }
+ }
+ ret |= successful_p;
+ }
+ if (ret && dump_file)
+ fprintf (dump_file, "Merging successful!\n");
+
+ return ret;
+}
+
+/* Coalesce the store_immediate_info objects recorded against the base object
+ BASE in the first phase and output them.
+ Delete the allocated structures.
+ Return true if any changes were made. */
+
+bool
+imm_store_chain_info::terminate_and_process_chain (tree base)
+{
+ /* Process store chain. */
+ bool ret = false;
+ if (m_store_info.length () > 1)
+ {
+ ret = coalesce_immediate_stores ();
+ if (ret)
+ ret = output_merged_stores (base);
+ }
+
+ /* Delete all the entries we allocated ourselves. */
+ store_immediate_info *info;
+ unsigned int i;
+ FOR_EACH_VEC_ELT (m_store_info, i, info)
+ delete info;
+
+ merged_store_group *merged_info;
+ FOR_EACH_VEC_ELT (m_merged_store_groups, i, merged_info)
+ delete merged_info;
+
+ return ret;
+}
+
+/* Return true iff LHS is a destination potentially interesting for
+ store merging. */
+
+static bool
+lhs_code_valid_for_store_merging_p (tree lhs)
+{
+ tree_code code = TREE_CODE (lhs);
+ tree type = TREE_TYPE (lhs);
+
+ /* If the target requests a promotion to a wider type get_inner_reference may
+ give bad results for the store destination (for example __fp16 to float
+ promotion in aarch64). Be conservative here. */
+ tree prom_type = targetm.promoted_type (type);
+ if (prom_type && TYPE_PRECISION (type) != TYPE_PRECISION (prom_type))
+ return false;
+
+ if (code == ARRAY_REF || code == ARRAY_RANGE_REF || code == MEM_REF
+ || code == COMPONENT_REF || code == BIT_FIELD_REF)
+ return true;
+
+ return false;
+}
+
+/* Return true if tree_code CODE is of a valid constant we want to consider
+ during store merging. In practice accept all codes that
+ native_encode_expr accepts. */
+
+static bool
+rhs_code_valid_for_store_merging_p (tree_code code)
+{
+ if (TREE_CODE_CLASS (code) != tcc_constant)
+ return false;
+
+ return code != VOID_CST;
+}
+
+/* Entry point for the pass. Go over each basic block recording chains of
+ immediate stores. Upon encountering a terminating statement (as defined
+ by stmt_terminates_chain_p) process the recorded stores and emit the widened
+ variants. */
+
+unsigned int
+pass_store_merging::execute (function *fun)
+{
+ basic_block bb;
+ hash_set<gimple *> orig_stmts;
+
+ FOR_EACH_BB_FN (bb, fun)
+ {
+ gimple_stmt_iterator gsi;
+ HOST_WIDE_INT num_statements = 0;
+ /* Record the original statements so that we can keep track of
+ statements emitted in this pass and not re-process new
+ statements. */
+ for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple_set_visited (gsi_stmt (gsi), false);
+ num_statements++;
+ }
+
+ if (num_statements < 2)
+ continue;
+
+ if (dump_file)
+ fprintf (dump_file, "Processing basic block <%d>:\n", bb->index);
+
+ for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple *stmt = gsi_stmt (gsi);
+
+ if (gimple_has_volatile_ops (stmt))
+ {
+ /* Terminate all chains. */
+ if (dump_file)
+ fprintf (dump_file, "Volatile access terminates "
+ "all chains\n");
+ terminate_and_process_all_chains ();
+ continue;
+ }
+
+ if (is_gimple_debug (stmt))
+ continue;
+
+ if (gimple_assign_single_p (stmt) && gimple_vdef (stmt)
+ && lhs_code_valid_for_store_merging_p (gimple_assign_lhs (stmt)))
+ {
+ tree lhs = gimple_assign_lhs (stmt);
+ tree rhs = gimple_assign_rhs1 (stmt);
+ tree_code rhs_code = gimple_assign_rhs_code (stmt);
+
+ HOST_WIDE_INT bitsize, bitpos;
+ machine_mode mode;
+ int unsignedp = 0, reversep = 0, volatilep = 0;
+ tree offset, base_addr;
+ base_addr
+ = get_inner_reference (lhs, &bitsize, &bitpos, &offset, &mode,
+ &unsignedp, &reversep, &volatilep);
+ gcc_assert (!volatilep);
+ bool invalid = offset || reversep || bitsize > MAX_STORE_BITSIZE
+ || !rhs_code_valid_for_store_merging_p (rhs_code);
+ struct imm_store_chain_info **chain_info
+ = m_stores.get (base_addr);
+
+ if (!invalid)
+ {
+ store_immediate_info *info;
+ if (chain_info)
+ {
+ info = new store_immediate_info (
+ bitsize, bitpos, rhs, lhs, stmt,
+ (*chain_info)->m_store_info.length ());
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "Recording immediate store from stmt:\n");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
+ (*chain_info)->m_store_info.safe_push (info);
+ continue;
+ }
+
+ /* Store aliases any existing chain? */
+ terminate_all_aliasing_chains (lhs, base_addr, stmt);
+ /* Start a new chain. */
+ struct imm_store_chain_info *new_chain
+ = new imm_store_chain_info;
+ info = new store_immediate_info (bitsize, bitpos, rhs, lhs,
+ stmt, 0);
+ new_chain->m_store_info.safe_push (info);
+ m_stores.put (base_addr, new_chain);
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "Starting new chain with statement:\n");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
+ }
+ else
+ terminate_all_aliasing_chains (lhs, base_addr, stmt);
+
+ continue;
+ }
+
+ terminate_all_aliasing_chains (NULL_TREE, NULL_TREE, stmt);
+ }
+ terminate_and_process_all_chains ();
+ }
+ return 0;
+}
+
+} // anon namespace
+
+/* Construct and return a store merging pass object. */
+
+gimple_opt_pass *
+make_pass_store_merging (gcc::context *ctxt)
+{
+ return new pass_store_merging (ctxt);
+}
diff --git a/gcc/opts.c b/gcc/opts.c
index bc0570dbd5ecf803737c32455060c51a16726c59..96d613c234cc251f19b0815c98a0e50136c08b21 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -463,6 +463,7 @@ static const struct default_options default_options_table[] =
{ OPT_LEVELS_1_PLUS, OPT_ftree_dse, NULL, 1 },
{ OPT_LEVELS_1_PLUS, OPT_ftree_ter, NULL, 1 },
{ OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_ftree_sra, NULL, 1 },
+ { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fstore_merging, NULL, 1 },
{ OPT_LEVELS_1_PLUS, OPT_ftree_fre, NULL, 1 },
{ OPT_LEVELS_1_PLUS, OPT_ftree_copy_prop, NULL, 1 },
{ OPT_LEVELS_1_PLUS, OPT_ftree_sink, NULL, 1 },
diff --git a/gcc/params.def b/gcc/params.def
index 8907aa4a0ffa5619b2b4022faa81db4fad89ce52..e63e5948089e1a6569cce386292d0d0890612256 100644
--- a/gcc/params.def
+++ b/gcc/params.def
@@ -1100,6 +1100,12 @@ DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
"Maximum amount of similar bbs to compare a bb with.",
10, 0, 0)
+DEFPARAM (PARAM_STORE_MERGING_ALLOW_UNALIGNED,
+ "store-merging-allow-unaligned",
+ "Allow the store merging pass to introduce unaligned stores "
+ "if it is legal to do so",
+ 1, 0, 1)
+
DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
"max-tail-merge-iterations",
"Maximum amount of iterations of the pass over a function.",
diff --git a/gcc/passes.def b/gcc/passes.def
index b8d87c3fb0348742c270b935c7914e1832f1dcd9..d5530e3ba072fb5ed4a1d43309cc019273249673 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -325,6 +325,7 @@ along with GCC; see the file COPYING3. If not see
NEXT_PASS (pass_phiopt);
NEXT_PASS (pass_fold_builtins);
NEXT_PASS (pass_optimize_widening_mul);
+ NEXT_PASS (pass_store_merging);
NEXT_PASS (pass_tail_calls);
/* If DCE is not run before checking for uninitialized uses,
we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr22141-1.c b/gcc/testsuite/gcc.c-torture/execute/pr22141-1.c
new file mode 100644
index 0000000000000000000000000000000000000000..7c888b469cf39f00ced8ddb8cc6dc245fa30b97b
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr22141-1.c
@@ -0,0 +1,122 @@
+/* PR middle-end/22141 */
+
+extern void abort (void);
+
+struct S
+{
+ struct T
+ {
+ char a;
+ char b;
+ char c;
+ char d;
+ } t;
+} u;
+
+struct U
+{
+ struct S s[4];
+};
+
+void __attribute__((noinline))
+c1 (struct T *p)
+{
+ if (p->a != 1 || p->b != 2 || p->c != 3 || p->d != 4)
+ abort ();
+ __builtin_memset (p, 0xaa, sizeof (*p));
+}
+
+void __attribute__((noinline))
+c2 (struct S *p)
+{
+ c1 (&p->t);
+}
+
+void __attribute__((noinline))
+c3 (struct U *p)
+{
+ c2 (&p->s[2]);
+}
+
+void __attribute__((noinline))
+f1 (void)
+{
+ u = (struct S) { { 1, 2, 3, 4 } };
+}
+
+void __attribute__((noinline))
+f2 (void)
+{
+ u.t.a = 1;
+ u.t.b = 2;
+ u.t.c = 3;
+ u.t.d = 4;
+}
+
+void __attribute__((noinline))
+f3 (void)
+{
+ u.t.d = 4;
+ u.t.b = 2;
+ u.t.a = 1;
+ u.t.c = 3;
+}
+
+void __attribute__((noinline))
+f4 (void)
+{
+ struct S v;
+ v.t.a = 1;
+ v.t.b = 2;
+ v.t.c = 3;
+ v.t.d = 4;
+ c2 (&v);
+}
+
+void __attribute__((noinline))
+f5 (struct S *p)
+{
+ p->t.a = 1;
+ p->t.c = 3;
+ p->t.d = 4;
+ p->t.b = 2;
+}
+
+void __attribute__((noinline))
+f6 (void)
+{
+ struct U v;
+ v.s[2].t.a = 1;
+ v.s[2].t.b = 2;
+ v.s[2].t.c = 3;
+ v.s[2].t.d = 4;
+ c3 (&v);
+}
+
+void __attribute__((noinline))
+f7 (struct U *p)
+{
+ p->s[2].t.a = 1;
+ p->s[2].t.c = 3;
+ p->s[2].t.d = 4;
+ p->s[2].t.b = 2;
+}
+
+int
+main (void)
+{
+ struct U w;
+ f1 ();
+ c2 (&u);
+ f2 ();
+ c1 (&u.t);
+ f3 ();
+ c2 (&u);
+ f4 ();
+ f5 (&u);
+ c2 (&u);
+ f6 ();
+ f7 (&w);
+ c3 (&w);
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr22141-2.c b/gcc/testsuite/gcc.c-torture/execute/pr22141-2.c
new file mode 100644
index 0000000000000000000000000000000000000000..cb9cc79026310260ffc3a83bfdf9bfc92f998a86
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr22141-2.c
@@ -0,0 +1,122 @@
+/* PR middle-end/22141 */
+
+extern void abort (void);
+
+struct S
+{
+ struct T
+ {
+ char a;
+ char b;
+ char c;
+ char d;
+ } t;
+} u __attribute__((aligned));
+
+struct U
+{
+ struct S s[4];
+};
+
+void __attribute__((noinline))
+c1 (struct T *p)
+{
+ if (p->a != 1 || p->b != 2 || p->c != 3 || p->d != 4)
+ abort ();
+ __builtin_memset (p, 0xaa, sizeof (*p));
+}
+
+void __attribute__((noinline))
+c2 (struct S *p)
+{
+ c1 (&p->t);
+}
+
+void __attribute__((noinline))
+c3 (struct U *p)
+{
+ c2 (&p->s[2]);
+}
+
+void __attribute__((noinline))
+f1 (void)
+{
+ u = (struct S) { { 1, 2, 3, 4 } };
+}
+
+void __attribute__((noinline))
+f2 (void)
+{
+ u.t.a = 1;
+ u.t.b = 2;
+ u.t.c = 3;
+ u.t.d = 4;
+}
+
+void __attribute__((noinline))
+f3 (void)
+{
+ u.t.d = 4;
+ u.t.b = 2;
+ u.t.a = 1;
+ u.t.c = 3;
+}
+
+void __attribute__((noinline))
+f4 (void)
+{
+ struct S v __attribute__((aligned));
+ v.t.a = 1;
+ v.t.b = 2;
+ v.t.c = 3;
+ v.t.d = 4;
+ c2 (&v);
+}
+
+void __attribute__((noinline))
+f5 (struct S *p)
+{
+ p->t.a = 1;
+ p->t.c = 3;
+ p->t.d = 4;
+ p->t.b = 2;
+}
+
+void __attribute__((noinline))
+f6 (void)
+{
+ struct U v __attribute__((aligned));
+ v.s[2].t.a = 1;
+ v.s[2].t.b = 2;
+ v.s[2].t.c = 3;
+ v.s[2].t.d = 4;
+ c3 (&v);
+}
+
+void __attribute__((noinline))
+f7 (struct U *p)
+{
+ p->s[2].t.a = 1;
+ p->s[2].t.c = 3;
+ p->s[2].t.d = 4;
+ p->s[2].t.b = 2;
+}
+
+int
+main (void)
+{
+ struct U w __attribute__((aligned));
+ f1 ();
+ c2 (&u);
+ f2 ();
+ c1 (&u.t);
+ f3 ();
+ c2 (&u);
+ f4 ();
+ f5 (&u);
+ c2 (&u);
+ f6 ();
+ f7 (&w);
+ c3 (&w);
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/store_merging_1.c b/gcc/testsuite/gcc.dg/store_merging_1.c
new file mode 100644
index 0000000000000000000000000000000000000000..09a4d1456c6db5c685cf872de688b4a5b9ef2c22
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_1.c
@@ -0,0 +1,35 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target non_strict_align } */
+/* { dg-options "-O -fdump-tree-store-merging" } */
+
+struct bar {
+ int a;
+ char b;
+ char c;
+ char d;
+ char e;
+ char f;
+ char g;
+};
+
+void
+foo1 (struct bar *p)
+{
+ p->b = 0;
+ p->a = 0;
+ p->c = 0;
+ p->d = 0;
+ p->e = 0;
+}
+
+void
+foo2 (struct bar *p)
+{
+ p->b = 0;
+ p->a = 0;
+ p->c = 1;
+ p->d = 0;
+ p->e = 0;
+}
+
+/* { dg-final { scan-tree-dump-times "Merging successful" 2 "store-merging" } } */
diff --git a/gcc/testsuite/gcc.dg/store_merging_2.c b/gcc/testsuite/gcc.dg/store_merging_2.c
new file mode 100644
index 0000000000000000000000000000000000000000..d3acc2d330c303a1db22c787e1ba8c89f4a423cc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_2.c
@@ -0,0 +1,80 @@
+/* { dg-do run } */
+/* { dg-require-effective-target non_strict_align } */
+/* { dg-options "-O -fdump-tree-store-merging" } */
+
+struct bar
+{
+ int a;
+ unsigned char b;
+ unsigned char c;
+ short d;
+ unsigned char e;
+ unsigned char f;
+ unsigned char g;
+};
+
+__attribute__ ((noinline)) void
+foozero (struct bar *p)
+{
+ p->b = 0;
+ p->a = 0;
+ p->c = 0;
+ p->d = 0;
+ p->e = 0;
+ p->f = 0;
+ p->g = 0;
+}
+
+__attribute__ ((noinline)) void
+foo1 (struct bar *p)
+{
+ p->b = 1;
+ p->a = 2;
+ p->c = 3;
+ p->d = 4;
+ p->e = 5;
+ p->f = 0;
+ p->g = 0xff;
+}
+
+__attribute__ ((noinline)) void
+foo2 (struct bar *p, struct bar *p2)
+{
+ p->b = 0xff;
+ p2->b = 0xa;
+ p->a = 0xfffff;
+ p2->c = 0xc;
+ p->c = 0xff;
+ p2->d = 0xbf;
+ p->d = 0xfff;
+}
+
+int
+main (void)
+{
+ struct bar b1, b2;
+ foozero (&b1);
+ foozero (&b2);
+
+ foo1 (&b1);
+ if (b1.b != 1 || b1.a != 2 || b1.c != 3 || b1.d != 4 || b1.e != 5
+ || b1.f != 0 || b1.g != 0xff)
+ __builtin_abort ();
+
+ foozero (&b1);
+ /* Make sure writes to aliasing struct pointers preserve the
+ correct order. */
+ foo2 (&b1, &b1);
+ if (b1.b != 0xa || b1.a != 0xfffff || b1.c != 0xff || b1.d != 0xfff)
+ __builtin_abort ();
+
+ foozero (&b1);
+ foo2 (&b1, &b2);
+ if (b1.a != 0xfffff || b1.b != 0xff || b1.c != 0xff || b1.d != 0xfff
+ || b2.b != 0xa || b2.c != 0xc || b2.d != 0xbf)
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "Merging successful" 2 "store-merging" } } */
diff --git a/gcc/testsuite/gcc.dg/store_merging_3.c b/gcc/testsuite/gcc.dg/store_merging_3.c
new file mode 100644
index 0000000000000000000000000000000000000000..cd756c1afaeb3338501971bc6a4b7c72f1a3c85d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_3.c
@@ -0,0 +1,32 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target non_strict_align } */
+/* { dg-options "-O -fdump-tree-store-merging" } */
+
+/* Make sure stores to volatile addresses don't get combined with
+ other accesses. */
+
+struct bar
+{
+ int a;
+ char b;
+ char c;
+ volatile short d;
+ char e;
+ char f;
+ char g;
+};
+
+void
+foozero (struct bar *p)
+{
+ p->b = 0xa;
+ p->a = 0xb;
+ p->c = 0xc;
+ p->d = 0;
+ p->e = 0xd;
+ p->f = 0xe;
+ p->g = 0xf;
+}
+
+/* { dg-final { scan-tree-dump "Volatile access terminates all chains" "store-merging" } } */
+/* { dg-final { scan-tree-dump-times "=\{v\} 0;" 1 "store-merging" } } */
diff --git a/gcc/testsuite/gcc.dg/store_merging_4.c b/gcc/testsuite/gcc.dg/store_merging_4.c
new file mode 100644
index 0000000000000000000000000000000000000000..4bf9025af6e9bd852a178057b1ed80d3bd86fc57
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_4.c
@@ -0,0 +1,32 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target non_strict_align } */
+/* { dg-options "-O -fdump-tree-store-merging" } */
+
+/* Check that we can merge interleaving stores that are guaranteed
+ to be non-aliasing. */
+
+struct bar
+{
+ int a;
+ char b;
+ char c;
+ short d;
+ char e;
+ char f;
+ char g;
+};
+
+void
+foozero (struct bar *restrict p, struct bar *restrict p2)
+{
+ p->b = 0xff;
+ p2->b = 0xa;
+ p->a = 0xfffff;
+ p2->a = 0xab;
+ p2->c = 0xc;
+ p->c = 0xff;
+ p2->d = 0xbf;
+ p->d = 0xfff;
+}
+
+/* { dg-final { scan-tree-dump-times "Merging successful" 2 "store-merging" } } */
diff --git a/gcc/testsuite/gcc.dg/store_merging_5.c b/gcc/testsuite/gcc.dg/store_merging_5.c
new file mode 100644
index 0000000000000000000000000000000000000000..3b824204e74266d447fd14b9f83bd3bb1dd25915
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_5.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target non_strict_align } */
+/* { dg-options "-O -fdump-tree-store-merging" } */
+
+/* Make sure that non-aliasing non-constant interspersed stores do not
+ stop chains. */
+
+struct bar {
+ int a;
+ char b;
+ char c;
+ char d;
+ char e;
+ char g;
+};
+
+void
+foo1 (struct bar *p, char tmp)
+{
+ p->a = 0;
+ p->b = 0;
+ p->g = tmp;
+ p->c = 0;
+ p->d = 0;
+ p->e = 0;
+}
+
+
+/* { dg-final { scan-tree-dump-times "Merging successful" 1 "store-merging" } } */
+/* { dg-final { scan-tree-dump-times "MEM\\\[.*\\\]" 1 "store-merging" } } */
diff --git a/gcc/testsuite/gcc.dg/store_merging_6.c b/gcc/testsuite/gcc.dg/store_merging_6.c
new file mode 100644
index 0000000000000000000000000000000000000000..7d89baf91b826e82c979092e4250fed650340d4d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_6.c
@@ -0,0 +1,53 @@
+/* { dg-do run } */
+/* { dg-require-effective-target non_strict_align } */
+/* { dg-options "-O -fdump-tree-store-merging" } */
+
+/* Check that we can widen accesses to bitfields. */
+
+struct bar {
+ int a : 3;
+ unsigned char b : 4;
+ unsigned char c : 1;
+ char d;
+ char e;
+ char f;
+ char g;
+};
+
+__attribute__ ((noinline)) void
+foozero (struct bar *p)
+{
+ p->b = 0;
+ p->a = 0;
+ p->c = 0;
+ p->d = 0;
+ p->e = 0;
+ p->f = 0;
+ p->g = 0;
+}
+
+__attribute__ ((noinline)) void
+foo1 (struct bar *p)
+{
+ p->b = 3;
+ p->a = 2;
+ p->c = 1;
+ p->d = 4;
+ p->e = 5;
+}
+
+int
+main (void)
+{
+ struct bar p;
+ foozero (&p);
+ foo1 (&p);
+ if (p.a != 2 || p.b != 3 || p.c != 1 || p.d != 4 || p.e != 5
+ || p.f != 0 || p.g != 0)
+ __builtin_abort ();
+
+ return 0;
+}
+
+
+/* { dg-final { scan-tree-dump-times "Merging successful" 2 "store-merging" } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/ldp_stp_1.c b/gcc/testsuite/gcc.target/aarch64/ldp_stp_1.c
index f02e55f1cc2f01063aea35b3b88f793bb2f7c532..9de4e771ab1e73bce960d4038f8ec5b49b5c612c 100644
--- a/gcc/testsuite/gcc.target/aarch64/ldp_stp_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/ldp_stp_1.c
@@ -3,22 +3,22 @@
int arr[4][4];
void
-foo ()
+foo (int x, int y)
{
- arr[0][1] = 1;
- arr[1][0] = -1;
- arr[2][0] = 1;
- arr[1][1] = -1;
- arr[0][2] = 1;
- arr[0][3] = -1;
- arr[1][2] = 1;
- arr[2][1] = -1;
- arr[3][0] = 1;
- arr[3][1] = -1;
- arr[2][2] = 1;
- arr[1][3] = -1;
- arr[2][3] = 1;
- arr[3][2] = -1;
+ arr[0][1] = x;
+ arr[1][0] = y;
+ arr[2][0] = x;
+ arr[1][1] = y;
+ arr[0][2] = x;
+ arr[0][3] = y;
+ arr[1][2] = x;
+ arr[2][1] = y;
+ arr[3][0] = x;
+ arr[3][1] = y;
+ arr[2][2] = x;
+ arr[1][3] = y;
+ arr[2][3] = x;
+ arr[3][2] = y;
}
/* { dg-final { scan-assembler-times "stp\tw\[0-9\]+, w\[0-9\]" 7 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/ldp_stp_4.c b/gcc/testsuite/gcc.target/aarch64/ldp_stp_4.c
index 40056b1adebd3fe3e473e378e123ee62041da9a2..824f0d2e81bc250f40ffb71b3e39cde76c9ff28d 100644
--- a/gcc/testsuite/gcc.target/aarch64/ldp_stp_4.c
+++ b/gcc/testsuite/gcc.target/aarch64/ldp_stp_4.c
@@ -3,22 +3,22 @@
float arr[4][4];
void
-foo ()
+foo (float x, float y)
{
- arr[0][1] = 1;
- arr[1][0] = -1;
- arr[2][0] = 1;
- arr[1][1] = -1;
- arr[0][2] = 1;
- arr[0][3] = -1;
- arr[1][2] = 1;
- arr[2][1] = -1;
- arr[3][0] = 1;
- arr[3][1] = -1;
- arr[2][2] = 1;
- arr[1][3] = -1;
- arr[2][3] = 1;
- arr[3][2] = -1;
+ arr[0][1] = x;
+ arr[1][0] = y;
+ arr[2][0] = x;
+ arr[1][1] = y;
+ arr[0][2] = x;
+ arr[0][3] = y;
+ arr[1][2] = x;
+ arr[2][1] = y;
+ arr[3][0] = x;
+ arr[3][1] = y;
+ arr[2][2] = x;
+ arr[1][3] = y;
+ arr[2][3] = x;
+ arr[3][2] = y;
}
/* { dg-final { scan-assembler-times "stp\ts\[0-9\]+, s\[0-9\]" 7 } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr22141.c b/gcc/testsuite/gcc.target/i386/pr22141.c
new file mode 100644
index 0000000000000000000000000000000000000000..efded365778417e7b4bf468288f42f5136fdd585
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr22141.c
@@ -0,0 +1,126 @@
+/* PR middle-end/22141 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+
+struct S
+{
+ struct T
+ {
+ char a;
+ char b;
+ char c;
+ char d;
+ } t;
+} u;
+
+struct U
+{
+ struct S s[4];
+};
+
+void __attribute__((noinline))
+c1 (struct T *p)
+{
+ if (p->a != 1 || p->b != 2 || p->c != 3 || p->d != 4)
+ abort ();
+ __builtin_memset (p, 0xaa, sizeof (*p));
+}
+
+void __attribute__((noinline))
+c2 (struct S *p)
+{
+ c1 (&p->t);
+}
+
+void __attribute__((noinline))
+c3 (struct U *p)
+{
+ c2 (&p->s[2]);
+}
+
+void __attribute__((noinline))
+f1 (void)
+{
+ u = (struct S) { { 1, 2, 3, 4 } };
+}
+
+void __attribute__((noinline))
+f2 (void)
+{
+ u.t.a = 1;
+ u.t.b = 2;
+ u.t.c = 3;
+ u.t.d = 4;
+}
+
+void __attribute__((noinline))
+f3 (void)
+{
+ u.t.d = 4;
+ u.t.b = 2;
+ u.t.a = 1;
+ u.t.c = 3;
+}
+
+void __attribute__((noinline))
+f4 (void)
+{
+ struct S v;
+ v.t.a = 1;
+ v.t.b = 2;
+ v.t.c = 3;
+ v.t.d = 4;
+ c2 (&v);
+}
+
+void __attribute__((noinline))
+f5 (struct S *p)
+{
+ p->t.a = 1;
+ p->t.c = 3;
+ p->t.d = 4;
+ p->t.b = 2;
+}
+
+void __attribute__((noinline))
+f6 (void)
+{
+ struct U v;
+ v.s[2].t.a = 1;
+ v.s[2].t.b = 2;
+ v.s[2].t.c = 3;
+ v.s[2].t.d = 4;
+ c3 (&v);
+}
+
+void __attribute__((noinline))
+f7 (struct U *p)
+{
+ p->s[2].t.a = 1;
+ p->s[2].t.c = 3;
+ p->s[2].t.d = 4;
+ p->s[2].t.b = 2;
+}
+
+int
+main (void)
+{
+ struct U w;
+ f1 ();
+ c2 (&u);
+ f2 ();
+ c1 (&u.t);
+ f3 ();
+ c2 (&u);
+ f4 ();
+ f5 (&u);
+ c2 (&u);
+ f6 ();
+ f7 (&w);
+ c3 (&w);
+ return 0;
+}
+
+/* { dg-final { scan-assembler-times "67305985\|4030201" 7 } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr34012.c b/gcc/testsuite/gcc.target/i386/pr34012.c
index 00b1240d1b9fb96fa558459bd4f357ad13a3881d..d0cffa052905a1c11e0927e92ab295d71517f746 100644
--- a/gcc/testsuite/gcc.target/i386/pr34012.c
+++ b/gcc/testsuite/gcc.target/i386/pr34012.c
@@ -1,7 +1,7 @@
/* PR rtl-optimization/34012 */
/* { dg-do compile } */
/* { dg-require-effective-target lp64 } */
-/* { dg-options "-O2" } */
+/* { dg-options "-O2 -fno-store-merging" } */
void bar (long int *);
void
diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index 105200b403403b25f0382b3a7ba5d5a28ca86ae1..3cadfb078b928ca4198db7e6a10886b223966044 100644
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -424,6 +424,7 @@ extern gimple_opt_pass *make_pass_late_warn_uninitialized (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_cse_reciprocals (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_cse_sincos (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_optimize_bswap (gcc::context *ctxt);
+extern gimple_opt_pass *make_pass_store_merging (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_optimize_widening_mul (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_warn_function_return (gcc::context *ctxt);
extern gimple_opt_pass *make_pass_warn_function_noreturn (gcc::context *ctxt);
