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* [gcc r14-4249] Fix PR 110386: backprop vs ABSU_EXPR
@ 2023-09-25 7:08 Andrew Pinski
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From: Andrew Pinski @ 2023-09-25 7:08 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:2bbac12ea7bd8a3eef5382e1b13f6019df4ec03f
commit r14-4249-g2bbac12ea7bd8a3eef5382e1b13f6019df4ec03f
Author: Andrew Pinski <apinski@marvell.com>
Date: Sat Sep 23 21:53:09 2023 -0700
Fix PR 110386: backprop vs ABSU_EXPR
The issue here is that when backprop tries to go
and strip sign ops, it skips over ABSU_EXPR but
ABSU_EXPR not only does an ABS, it also changes the
type to unsigned.
Since strip_sign_op_1 is only supposed to strip off
sign changing operands and not ones that change types,
removing ABSU_EXPR here is correct. We don't handle
nop conversions so this does cause any missed optimizations either.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
PR tree-optimization/110386
gcc/ChangeLog:
* gimple-ssa-backprop.cc (strip_sign_op_1): Remove ABSU_EXPR.
gcc/testsuite/ChangeLog:
* gcc.c-torture/compile/pr110386-1.c: New test.
* gcc.c-torture/compile/pr110386-2.c: New test.
Diff:
---
gcc/gimple-ssa-backprop.cc | 1 -
gcc/testsuite/gcc.c-torture/compile/pr110386-1.c | 9 +++++++++
gcc/testsuite/gcc.c-torture/compile/pr110386-2.c | 11 +++++++++++
3 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/gcc/gimple-ssa-backprop.cc b/gcc/gimple-ssa-backprop.cc
index 65a65590017..dcb15ed4f61 100644
--- a/gcc/gimple-ssa-backprop.cc
+++ b/gcc/gimple-ssa-backprop.cc
@@ -694,7 +694,6 @@ strip_sign_op_1 (tree rhs)
switch (gimple_assign_rhs_code (assign))
{
case ABS_EXPR:
- case ABSU_EXPR:
case NEGATE_EXPR:
return gimple_assign_rhs1 (assign);
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr110386-1.c b/gcc/testsuite/gcc.c-torture/compile/pr110386-1.c
new file mode 100644
index 00000000000..4fcc977ad16
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr110386-1.c
@@ -0,0 +1,9 @@
+
+int f(int a)
+{
+ int c = c < 0 ? c : -c;
+ c = -c;
+ unsigned b = c;
+ unsigned t = b*a;
+ return t*t;
+}
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr110386-2.c b/gcc/testsuite/gcc.c-torture/compile/pr110386-2.c
new file mode 100644
index 00000000000..c60e1b6994b
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr110386-2.c
@@ -0,0 +1,11 @@
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-mavx" } */
+
+#include <immintrin.h>
+
+__m128i do_stuff(__m128i XMM0) {
+ __m128i ABS0 = _mm_abs_epi32(XMM0);
+ __m128i MUL0 = _mm_mullo_epi32(ABS0, XMM0);
+ __m128i MUL1 = _mm_mullo_epi32(MUL0, MUL0);
+ return MUL1;
+}
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