Hi!
The following testcase ICEs in the movabsq $(i32 << shift), r64 peephole2
I've added a while back to use smaller code than movabsq if possible.
If i32 is 0xfa1e0ff3 and shift is not divisible by 8, then it creates
an invalid insn (as 0xfa1e0ff3 CONST_INT is not allowed as
x86_64_immediate_operand nor x86_64_zext_immediate_operand), the peephole2
even triggers on it again and again (this time with shift 0) until it gives
up.
The following patch fixes that. As ix86_endbr_immediate_operand needs a
CONST_INT and it is hopefully rare, I chose to use FAIL rather than handling
it in the condition (where I'd probably need to call ctz_hwi again etc.).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2023-12-04 Jakub Jelinek <ja...@redhat.com>
PR target/112845
* config/i386/i386.md (movabsq $(i32 << shift), r64 peephole2): FAIL
if the new immediate is ix86_endbr_immediate_operand.
--- gcc/config/i386/i386.md.jj 2023-12-01 08:10:42.287330513 +0100
+++ gcc/config/i386/i386.md 2023-12-04 16:22:23.497986229 +0100
@@ -2699,7 +2699,10 @@ (define_peephole2
(clobber (reg:CC FLAGS_REG))])]
{
int shift = ctz_hwi (UINTVAL (operands[1]));
- operands[1] = gen_int_mode (UINTVAL (operands[1]) >> shift, DImode);
+ rtx op1 = gen_int_mode (UINTVAL (operands[1]) >> shift, DImode);
+ if (ix86_endbr_immediate_operand (op1, VOIDmode))
+ FAIL;
+ operands[1] = op1;
operands[2] = gen_int_mode (shift, QImode);
})
--- gcc/testsuite/gcc.dg/pr112845.c.jj 2023-12-04 16:25:31.228350449 +0100
+++ gcc/testsuite/gcc.dg/pr112845.c 2023-12-04 16:25:26.740413464 +0100
@@ -0,0 +1,9 @@
+/* PR target/112845 */
+/* { dg-do compile { target cet } } */
+/* { dg-options "-Os -fcf-protection" } */
+
+unsigned long long
+foo (void)
+{
+ return 0xfa1e0ff3ULL << 3;
+}
Jakub
