This patch adds a magic OSC (operand store compare) break instruction
which is necessary if a store is followed closely by a load with same
base+indx+displ while either base or index get modified in between.
The patch improves several SpecCPU testcases running on IBM z13.
I'll wait a few days for comments before committing the patch.
Bye,
-Andreas-
gcc/testsuite/ChangeLog:
2016-10-14 Andreas Krebbel <kreb...@linux.vnet.ibm.com>
* gcc.target/s390/oscbreak-1.c: New test.
gcc/ChangeLog:
2016-10-14 Andreas Krebbel <kreb...@linux.vnet.ibm.com>
* config/s390/s390.c (s390_adjust_loop_scan_osc): New function.
(s390_adjust_loops): New function.
(s390_reorg): Invoke s390_adjust_loops.
* config/s390/s390.md: (UNSPEC_OSC_BREAK): New constant.
("osc_break"): New insn definition.
---
gcc/config/s390/s390.c | 152 +++++++++++++++++++++++++++++
gcc/config/s390/s390.md | 8 ++
gcc/testsuite/gcc.target/s390/oscbreak-1.c | 25 +++++
3 files changed, 185 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/s390/oscbreak-1.c
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index f69b470..3554f33 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -13502,6 +13502,155 @@ s390_z10_optimize_cmp (rtx_insn *insn)
return insn_added_p;
}
+/* Number of INSNs to be scanned backward in the last BB of the loop
+ and forward in the first BB of the loop. This usually should be a
+ bit more than the number of INSNs which could go into one
+ group. */
+#define S390_OSC_SCAN_INSN_NUM 5
+
+/* Scan LOOP for static OSC collisions and return true if a osc_break
+ should be issued for this loop. */
+static bool
+s390_adjust_loop_scan_osc (struct loop* loop)
+
+{
+ HARD_REG_SET modregs, newregs;
+ rtx_insn *insn, *store_insn = NULL;
+ rtx set;
+ struct s390_address addr_store, addr_load;
+ subrtx_iterator::array_type array;
+ int insn_count;
+
+ CLEAR_HARD_REG_SET (modregs);
+
+ insn_count = 0;
+ FOR_BB_INSNS_REVERSE (loop->latch, insn)
+ {
+ if (!INSN_P (insn) || INSN_CODE (insn) <= 0)
+ continue;
+
+ insn_count++;
+ if (insn_count > S390_OSC_SCAN_INSN_NUM)
+ return false;
+
+ find_all_hard_reg_sets (insn, &newregs, true);
+ IOR_HARD_REG_SET (modregs, newregs);
+
+ set = single_set (insn);
+ if (!set)
+ continue;
+
+ if (MEM_P (SET_DEST (set))
+ && s390_decompose_address (XEXP (SET_DEST (set), 0), &addr_store))
+ {
+ store_insn = insn;
+ break;
+ }
+ }
+
+ if (store_insn == NULL_RTX)
+ return false;
+
+ insn_count = 0;
+ FOR_BB_INSNS (loop->header, insn)
+ {
+ if (!INSN_P (insn) || INSN_CODE (insn) <= 0)
+ continue;
+
+ if (insn == store_insn)
+ return false;
+
+ insn_count++;
+ if (insn_count > S390_OSC_SCAN_INSN_NUM)
+ return false;
+
+ find_all_hard_reg_sets (insn, &newregs, true);
+ IOR_HARD_REG_SET (modregs, newregs);
+
+ set = single_set (insn);
+ if (!set)
+ continue;
+
+ /* An intermediate store disrupts static OSC checking
+ anyway. */
+ if (MEM_P (SET_DEST (set))
+ && s390_decompose_address (XEXP (SET_DEST (set), 0), NULL))
+ return false;
+
+ FOR_EACH_SUBRTX (iter, array, SET_SRC (set), NONCONST)
+ if (MEM_P (*iter)
+ && s390_decompose_address (XEXP (*iter, 0), &addr_load)
+ && rtx_equal_p (addr_load.base, addr_store.base)
+ && rtx_equal_p (addr_load.indx, addr_store.indx)
+ && rtx_equal_p (addr_load.disp, addr_store.disp))
+ {
+ if ((addr_load.base != NULL_RTX
+ && TEST_HARD_REG_BIT (modregs, REGNO (addr_load.base)))
+ || (addr_load.indx != NULL_RTX
+ && TEST_HARD_REG_BIT (modregs, REGNO (addr_load.indx))))
+ return true;
+ }
+ }
+ return false;
+}
+
+/* Look for adjustments which can be done on simple innermost
+ loops. */
+static void
+s390_adjust_loops ()
+{
+ struct loop *loop = NULL;
+
+ df_analyze ();
+ compute_bb_for_insn ();
+
+ /* Find the loops. */
+ loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
+
+ FOR_EACH_LOOP (loop, LI_ONLY_INNERMOST)
+ {
+ if (dump_file)
+ {
+ flow_loop_dump (loop, dump_file, NULL, 0);
+ fprintf (dump_file, ";; OSC loop scan Loop: ");
+ }
+ if (loop->latch == NULL
+ || pc_set (BB_END (loop->latch)) == NULL_RTX
+ || !s390_adjust_loop_scan_osc (loop))
+ {
+ if (dump_file)
+ {
+ if (loop->latch == NULL)
+ fprintf (dump_file, " muliple backward jumps\n");
+ else
+ {
+ fprintf (dump_file, " header insn: %d latch insn: %d ",
+ INSN_UID (BB_HEAD (loop->header)),
+ INSN_UID (BB_END (loop->latch)));
+ if (pc_set (BB_END (loop->latch)) == NULL_RTX)
+ fprintf (dump_file, " loop does not end with jump\n");
+ else
+ fprintf (dump_file, " not instrumented\n");
+ }
+ }
+ }
+ else
+ {
+ rtx_insn *new_insn;
+
+ if (dump_file)
+ fprintf (dump_file, " adding OSC break insn: ");
+ new_insn = emit_insn_before (gen_osc_break (),
+ BB_END (loop->latch));
+ INSN_ADDRESSES_NEW (new_insn, -1);
+ }
+ }
+
+ loop_optimizer_finalize ();
+
+ df_finish_pass (false);
+}
+
/* Perform machine-dependent processing. */
static void
@@ -13510,6 +13659,9 @@ s390_reorg (void)
bool pool_overflow = false;
int hw_before, hw_after;
+ if (s390_tune == PROCESSOR_2964_Z13)
+ s390_adjust_loops ();
+
/* Make sure all splits have been performed; splits after
machine_dependent_reorg might confuse insn length counts. */
split_all_insns_noflow ();
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 9de442f..d97a811 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -280,6 +280,8 @@
; Split stack support
UNSPECV_SPLIT_STACK_CALL
UNSPECV_SPLIT_STACK_DATA
+
+ UNSPECV_OSC_BREAK
])
;;
@@ -11196,3 +11198,9 @@
"jg%C1\t%0"
[(set_attr "op_type" "RIL")
(set_attr "type" "branch")])
+
+(define_insn "osc_break"
+ [(unspec_volatile [(const_int 0)] UNSPECV_OSC_BREAK)]
+ ""
+ "bcr\t7,%%r0"
+ [(set_attr "op_type" "RR")])
diff --git a/gcc/testsuite/gcc.target/s390/oscbreak-1.c
b/gcc/testsuite/gcc.target/s390/oscbreak-1.c
new file mode 100644
index 0000000..fdf356c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/oscbreak-1.c
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -mtune=z13 -dp" } */
+
+void
+foo (char *a, int b)
+{
+ int i;
+
+ for (i = 0; i < b; i++)
+ a[i] += 1;
+}
+
+void
+bar (char *a, int b)
+{
+ int i;
+
+ for (i = 0; i < b; i++)
+ {
+ if (a[i] & 1)
+ a[i] = 1;
+ }
+}
+
+/* { dg-final { scan-assembler "osc_break" } } */
--
2.9.1
