Hi!
The following testcase ICEs starting with GCC 12 since r12-4526
although the bug has been introduced already in r12-2751.
The problem was in the addition of cond_<code><mode> define_expand
which uses nonimmediate_operand predicates for both maxmin operands
for all VI1248_AVX512VLBW modes. It works fine with
VI48_AVX512VL modes because the <code><mode>3_mask VI48_AVX512VL
define_expand uses ix86_fixup_binary_operands_no_copy and the
*avx512f_<code><mode>3<mask_name> VI48_AVX512VL define_insn uses
% in constraint and !(MEM_P && MEM_P) check in condition (and
<code><mode>3 define_expand with VI124_256_AVX512F_AVX512BW iterator
does that too), but eventhough the 8-bit and 16-bit element maxmin
is commutative too, the <mask_codefor><code><mode>3<mask_name>
define_insn with VI12_AVX512VL iterator didn't use % in constraint
to make it commutative. So, e.g. cond_umaxv32qi define_expand
allowed nonimmediate_operand for both umax operands, but used
gen_umaxv32qi_mask which wasn't commutative and only allowed
nonimmediate_operand for the second operand.
The following patch fixes it by keeping the <code><mode>3
VI124_256_AVX512F_AVX512BW define_expand as is (it does
ix86_fixup_binary_operands_no_copy) but extending the
<code><mode>3_mask define_expand from VI48_AVX512VL to
VI1248_AVX512VLBW which keeps the current modes with their
ISA conditions and adds the VI12_AVX512VL modes under additional
TARGET_AVX512BW condition, and turning the actual define_insn
into an * prefixed name (which it was before just for the non-masked
case) and having the same commutative operand handling as in other
define_insns.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2025-02-07 Jakub Jelinek <ja...@redhat.com>
PR target/118776
* config/i386/sse.md (<code><mode>3_mask): Use VI1248_AVX512VLBW
iterator rather than VI48_AVX512VL.
(<mask_codefor><code><mode>3<mask_name>): Rename to ...
(*avx512bw_<code><mode>3<mask_name>): ... this. Use
nonimmediate_operand rather than register_operand predicate and %v
rather than v constraint for operand 1 and adjust condition to reject
MEMs in both operand 1 and 2.
* gcc.target/i386/pr118776.c: New test.
--- gcc/config/i386/sse.md.jj 2025-01-23 15:54:53.160911648 +0100
+++ gcc/config/i386/sse.md 2025-02-07 00:16:49.155363094 +0100
@@ -17703,12 +17703,12 @@ (define_expand "cond_<code><mode>"
})
(define_expand "<code><mode>3_mask"
- [(set (match_operand:VI48_AVX512VL 0 "register_operand")
- (vec_merge:VI48_AVX512VL
- (maxmin:VI48_AVX512VL
- (match_operand:VI48_AVX512VL 1 "nonimmediate_operand")
- (match_operand:VI48_AVX512VL 2 "nonimmediate_operand"))
- (match_operand:VI48_AVX512VL 3 "nonimm_or_0_operand")
+ [(set (match_operand:VI1248_AVX512VLBW 0 "register_operand")
+ (vec_merge:VI1248_AVX512VLBW
+ (maxmin:VI1248_AVX512VLBW
+ (match_operand:VI1248_AVX512VLBW 1 "nonimmediate_operand")
+ (match_operand:VI1248_AVX512VLBW 2 "nonimmediate_operand"))
+ (match_operand:VI1248_AVX512VLBW 3 "nonimm_or_0_operand")
(match_operand:<avx512fmaskmode> 4 "register_operand")))]
"TARGET_AVX512F"
"ix86_fixup_binary_operands_no_copy (<CODE>, <MODE>mode, operands);")
@@ -17724,12 +17724,12 @@ (define_insn "*avx512f_<code><mode>3<mas
(set_attr "prefix" "maybe_evex")
(set_attr "mode" "<sseinsnmode>")])
-(define_insn "<mask_codefor><code><mode>3<mask_name>"
+(define_insn "*avx512bw_<code><mode>3<mask_name>"
[(set (match_operand:VI12_AVX512VL 0 "register_operand" "=v")
(maxmin:VI12_AVX512VL
- (match_operand:VI12_AVX512VL 1 "register_operand" "v")
+ (match_operand:VI12_AVX512VL 1 "nonimmediate_operand" "%v")
(match_operand:VI12_AVX512VL 2 "nonimmediate_operand" "vm")))]
- "TARGET_AVX512BW"
+ "TARGET_AVX512BW && !(MEM_P (operands[1]) && MEM_P (operands[2]))"
"vp<maxmin_int><ssemodesuffix>\t{%2, %1,
%0<mask_operand3>|%0<mask_operand3>, %1, %2}"
[(set_attr "type" "sseiadd")
(set_attr "prefix" "evex")
--- gcc/testsuite/gcc.target/i386/pr118776.c.jj 2025-02-07 08:41:46.054157905
+0100
+++ gcc/testsuite/gcc.target/i386/pr118776.c 2025-02-07 08:40:30.508196302
+0100
@@ -0,0 +1,23 @@
+/* PR target/118776 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx512bw -mavx512vl" } */
+
+void bar (unsigned char *);
+
+void
+foo (unsigned char *x)
+{
+ unsigned char b[32];
+ bar (b);
+ for (int i = 0; i < 32; i++)
+ {
+ unsigned char c = 8;
+ if (i > 3)
+ {
+ unsigned char d = b[i];
+ d = 1 > d ? 1 : d;
+ c = d;
+ }
+ x[i] = c;
+ }
+}
Jakub
