[pushed,PR108999] LRA: For clobbered regs use operand mode instead of the biggest mode
Commit Message
The following patch solves
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108999
The patch was successfully bootstrapped and tested on i686, x86-64,
aarch64, and ppc64 be/le.
commit 3c75631fc09a22f2513fab80ef502c2a8b0f9121
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Thu Mar 9 08:41:09 2023 -0500
LRA: For clobbered regs use operand mode instead of the biggest mode
LRA is too conservative in calculation of conflicts with clobbered regs by
using the biggest access mode. This results in failure of possible reg
coalescing and worse code. This patch solves the problem.
PR rtl-optimization/108999
gcc/ChangeLog:
* lra-constraints.cc (process_alt_operands): Use operand modes for
clobbered regs instead of the biggest access mode.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/pr108999.c: New.
@@ -3108,7 +3108,8 @@ process_alt_operands (int only_alternative)
lra_assert (operand_reg[i] != NULL_RTX);
clobbered_hard_regno = hard_regno[i];
CLEAR_HARD_REG_SET (temp_set);
- add_to_hard_reg_set (&temp_set, biggest_mode[i], clobbered_hard_regno);
+ add_to_hard_reg_set (&temp_set, GET_MODE (*curr_id->operand_loc[i]),
+ clobbered_hard_regno);
first_conflict_j = last_conflict_j = -1;
for (j = 0; j < n_operands; j++)
if (j == i
new file mode 100644
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=armv8.2-a+sve" } */
+#include <arm_sve.h>
+
+void subreg_coalesce5 (
+ svbool_t pg, int64_t* base, int n,
+ int64_t *in1, int64_t *in2, int64_t*out
+)
+{
+ svint64x2_t result = svld2_s64 (pg, base);
+
+ for (int i = 0; i < n; i += 1) {
+ svint64_t v18 = svld1_s64(pg, in1 + i);
+ svint64_t v19 = svld1_s64(pg, in2 + i);
+ result.__val[0] = svmad_s64_z(pg, v18, v19, result.__val[0]);
+ result.__val[1] = svmad_s64_z(pg, v18, v19, result.__val[1]);
+ }
+ svst2_s64(pg, out, result);
+}
+
+/* { dg-final { scan-assembler-not {[ \t]*mov[ \t]*z[0-9]+\.d} } } */