https://gcc.gnu.org/g:09f0768b55b96c861811a8989d7c1cc59b4c29b6
commit r16-2727-g09f0768b55b96c861811a8989d7c1cc59b4c29b6
Author: H.J. Lu <hjl.to...@gmail.com>
Date: Fri Aug 1 05:02:18 2025 -0700
x86: Don't hoist non all 0s/1s vector set outside of loop
Don't hoist non all 0s/1s vector set outside of the loop to avoid extra
spills.
gcc/
PR target/120941
* config/i386/i386-features.cc (x86_cse_kind): Moved before
ix86_place_single_vector_set.
(redundant_load): Likewise.
(ix86_place_single_vector_set): Replace the last argument to the
pointer to redundant_load. For X86_CSE_VEC_DUP, don't place the
vector set outside of the loop to avoid extra spills.
(remove_redundant_vector_load): Pass load to
ix86_place_single_vector_set.
gcc/testsuite/
PR target/120941
* gcc.target/i386/pr120941-1.c: New test.
Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
Diff:
---
gcc/config/i386/i386-features.cc | 107 +++++++++++++++--------------
gcc/testsuite/gcc.target/i386/pr120941-1.c | 49 +++++++++++++
2 files changed, 106 insertions(+), 50 deletions(-)
diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
index 53e86c8a4931..9941e61361c7 100644
--- a/gcc/config/i386/i386-features.cc
+++ b/gcc/config/i386/i386-features.cc
@@ -3085,21 +3085,63 @@ ix86_rpad_gate ()
&& optimize_function_for_speed_p (cfun));
}
+enum x86_cse_kind
+{
+ X86_CSE_CONST0_VECTOR,
+ X86_CSE_CONSTM1_VECTOR,
+ X86_CSE_VEC_DUP
+};
+
+struct redundant_load
+{
+ /* Bitmap of basic blocks with broadcast instructions. */
+ auto_bitmap bbs;
+ /* Bitmap of broadcast instructions. */
+ auto_bitmap insns;
+ /* The broadcast inner scalar. */
+ rtx val;
+ /* The inner scalar mode. */
+ machine_mode mode;
+ /* The instruction which sets the inner scalar. Nullptr if the inner
+ scalar is applied to the whole function, instead of within the same
+ block. */
+ rtx_insn *def_insn;
+ /* The widest broadcast source. */
+ rtx broadcast_source;
+ /* The widest broadcast register. */
+ rtx broadcast_reg;
+ /* The basic block of the broadcast instruction. */
+ basic_block bb;
+ /* The number of broadcast instructions with the same inner scalar. */
+ unsigned HOST_WIDE_INT count;
+ /* The threshold of broadcast instructions with the same inner
+ scalar. */
+ unsigned int threshold;
+ /* The widest broadcast size in bytes. */
+ unsigned int size;
+ /* Load kind. */
+ x86_cse_kind kind;
+};
+
/* Generate a vector set, DEST = SRC, at entry of the nearest dominator
for basic block map BBS, which is in the fake loop that contains the
whole function, so that there is only a single vector set in the
- whole function. If not nullptr, INNER_SCALAR is the inner scalar of
- SRC, as (reg:SI 99) in (vec_duplicate:V4SI (reg:SI 99)). */
+ whole function. If not nullptr, LOAD is a pointer to the load. */
static void
ix86_place_single_vector_set (rtx dest, rtx src, bitmap bbs,
- rtx inner_scalar = nullptr)
+ redundant_load *load = nullptr)
{
basic_block bb = nearest_common_dominator_for_set (CDI_DOMINATORS, bbs);
- while (bb->loop_father->latch
- != EXIT_BLOCK_PTR_FOR_FN (cfun))
- bb = get_immediate_dominator (CDI_DOMINATORS,
- bb->loop_father->header);
+ /* For X86_CSE_VEC_DUP, don't place the vector set outside of the loop
+ to avoid extra spills. */
+ if (!load || load->kind != X86_CSE_VEC_DUP)
+ {
+ while (bb->loop_father->latch
+ != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ bb = get_immediate_dominator (CDI_DOMINATORS,
+ bb->loop_father->header);
+ }
rtx set = gen_rtx_SET (dest, src);
@@ -3141,8 +3183,14 @@ ix86_place_single_vector_set (rtx dest, rtx src, bitmap
bbs,
}
}
- if (inner_scalar)
+ if (load && load->kind == X86_CSE_VEC_DUP)
{
+ /* Get the source from LOAD as (reg:SI 99) in
+
+ (vec_duplicate:V4SI (reg:SI 99))
+
+ */
+ rtx inner_scalar = load->val;
/* Set the source in (vec_duplicate:V4SI (reg:SI 99)). */
rtx reg = XEXP (src, 0);
if ((REG_P (inner_scalar) || MEM_P (inner_scalar))
@@ -3489,44 +3537,6 @@ replace_vector_const (machine_mode vector_mode, rtx
vector_const,
}
}
-enum x86_cse_kind
-{
- X86_CSE_CONST0_VECTOR,
- X86_CSE_CONSTM1_VECTOR,
- X86_CSE_VEC_DUP
-};
-
-struct redundant_load
-{
- /* Bitmap of basic blocks with broadcast instructions. */
- auto_bitmap bbs;
- /* Bitmap of broadcast instructions. */
- auto_bitmap insns;
- /* The broadcast inner scalar. */
- rtx val;
- /* The inner scalar mode. */
- machine_mode mode;
- /* The instruction which sets the inner scalar. Nullptr if the inner
- scalar is applied to the whole function, instead of within the same
- block. */
- rtx_insn *def_insn;
- /* The widest broadcast source. */
- rtx broadcast_source;
- /* The widest broadcast register. */
- rtx broadcast_reg;
- /* The basic block of the broadcast instruction. */
- basic_block bb;
- /* The number of broadcast instructions with the same inner scalar. */
- unsigned HOST_WIDE_INT count;
- /* The threshold of broadcast instructions with the same inner
- scalar. */
- unsigned int threshold;
- /* The widest broadcast size in bytes. */
- unsigned int size;
- /* Load kind. */
- x86_cse_kind kind;
-};
-
/* Return the inner scalar if OP is a broadcast, else return nullptr. */
static rtx
@@ -3872,10 +3882,7 @@ remove_redundant_vector_load (void)
else
ix86_place_single_vector_set (load->broadcast_reg,
load->broadcast_source,
- load->bbs,
- (load->kind == X86_CSE_VEC_DUP
- ? load->val
- : nullptr));
+ load->bbs, load);
}
loop_optimizer_finalize ();
diff --git a/gcc/testsuite/gcc.target/i386/pr120941-1.c
b/gcc/testsuite/gcc.target/i386/pr120941-1.c
new file mode 100644
index 000000000000..b4fc6ac97fc2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr120941-1.c
@@ -0,0 +1,49 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -march=x86-64-v3" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target lp64 } {^\t?\.} } }
*/
+
+/*
+**bar:
+**.LFB[0-9]+:
+**...
+** vbroadcastsd .LC4\(%rip\), %ymm2
+** leal 2\(%rbx\), %eax
+** vbroadcastsd .LC2\(%rip\), %ymm4
+** negl %eax
+**...
+*/
+
+extern void foo (int);
+
+enum { N_CELL_ENTRIES1 = 2 }
+typedef LBM_Grid1[64];
+enum { N_CELL_ENTRIES2 = 2 }
+typedef LBM_Grid2[64];
+LBM_Grid1 grid1;
+LBM_Grid2 grid2;
+extern int n;
+
+void
+LBM_handleInOutFlow()
+{
+ int i, j;
+ for (; i; i += 2)
+ {
+ for (j = 0; j < n; j++)
+ {
+ grid1[i] = 1.0 / 36.0 * i;
+ grid2[i] = 1.0 / 36.0 * i;
+ }
+ }
+}
+
+int main_t;
+void
+bar (void)
+{
+ for (; main_t; main_t++) {
+ LBM_handleInOutFlow();
+ foo (main_t);
+ }
+}
