Hi!
The following testcase ICEs, because cbranchv16qi4 expansion calls
ix86_expand_branch with op1 being a pre-AVX unaligned memory and
ix86_expand_branch emits a xorv16qi3 instruction without making sure
the operand predicates are satisfied.
While I could manually check if the argument (or both?) doesn't
match vector_operand predicate (apparently this one or bcst_vector_operand
is used in all integral 16+ bytes *xorv*3 instructions) force it into a
register, but as all gen_xorv*3 expanders call
ix86_expand_vector_logical_operator, it seems easier to just call that
function which ensures the right thing happens. Calling the individual
gen_xorv*3 functions would mean ugly switch on the modes and using high
level expand_simple_binop here seems too high level to me.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2023-11-23 Jakub Jelinek <ja...@redhat.com>
PR target/112681
* config/i386/i386-expand.cc (ix86_expand_branch): Use
ix86_expand_vector_logical_operator to expand vector XOR rather than
gen_rtx_SET on gen_rtx_XOR.
* gcc.target/i386/sse4-pr112681.c: New test.
--- gcc/config/i386/i386-expand.cc.jj 2023-11-21 09:31:35.792395304 +0100
+++ gcc/config/i386/i386-expand.cc 2023-11-23 20:57:57.128721762 +0100
@@ -2453,7 +2453,8 @@ ix86_expand_branch (enum rtx_code code,
/* Generate XOR since we can't check that one operand is zero
vector. */
tmp = gen_reg_rtx (mode);
- emit_insn (gen_rtx_SET (tmp, gen_rtx_XOR (mode, op0, op1)));
+ rtx ops[3] = { tmp, op0, op1 };
+ ix86_expand_vector_logical_operator (XOR, mode, ops);
tmp = gen_lowpart (p_mode, tmp);
emit_insn (gen_rtx_SET (gen_rtx_REG (CCZmode, FLAGS_REG),
gen_rtx_UNSPEC (CCZmode,
--- gcc/testsuite/gcc.target/i386/sse4-pr112681.c.jj 2023-11-23
21:01:57.983361917 +0100
+++ gcc/testsuite/gcc.target/i386/sse4-pr112681.c 2023-11-23
21:01:42.054584121 +0100
@@ -0,0 +1,11 @@
+/* PR target/112681 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse4 -mno-avx" } */
+
+struct S { void *c; char d[16]; } a, b;
+
+int
+foo (void)
+{
+ return __builtin_memcmp (a.d, b.d, sizeof (a.d)) != 0;
+}
Jakub
