https://gcc.gnu.org/g:dbfc2d075f10149bd94e16c1210ffe4bac7e60c3
commit r11-11422-gdbfc2d075f10149bd94e16c1210ffe4bac7e60c3 Author: Andrew Pinski <apin...@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.c (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. (cherry picked from commit 2bbac12ea7bd8a3eef5382e1b13f6019df4ec03f) Diff: --- gcc/gimple-ssa-backprop.c | 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.c b/gcc/gimple-ssa-backprop.c index 4b62bb92a21d..8c0a37e6e97d 100644 --- a/gcc/gimple-ssa-backprop.c +++ b/gcc/gimple-ssa-backprop.c @@ -688,7 +688,6 @@ 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 000000000000..4fcc977ad16f --- /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 000000000000..c60e1b6994b7 --- /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; +}