[gcc r14-8436] aarch64: Fix undefinedness while testing the J constraint [PR100204]

[gcc r14-8436] aarch64: Fix undefinedness while testing the J constraint [PR100204]

[Andrew Pinski]

https://gcc.gnu.org/g:f03b8f595b6350732bb0a9a69557c5ed2af085b2

commit r14-8436-gf03b8f595b6350732bb0a9a69557c5ed2af085b2
Author: Andrew Pinski <quic_apinski@quicinc.com>
Date:   Thu Jan 25 08:30:36 2024 -0800

    aarch64: Fix undefinedness while testing the J constraint [PR100204]
    
    The J constraint can invoke undefined behavior due to it taking the
    negative of the ival if ival was HWI_MIN. The fix is simple as casting
    to `unsigned HOST_WIDE_INT` before doing the negative of it. This
    does that.
    
    Committed as obvious after build/test for aarch64-linux-gnu.
    
    gcc/ChangeLog:
    
            PR target/100204
            * config/aarch64/constraints.md (J): Cast to `unsigned HOST_WIDE_INT`
            before taking the negative of it.
    
    Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

Diff:
---
 gcc/config/aarch64/constraints.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/config/aarch64/constraints.md b/gcc/config/aarch64/constraints.md
index 8566befd7271..a2569cea5102 100644
--- a/gcc/config/aarch64/constraints.md
+++ b/gcc/config/aarch64/constraints.md
@@ -118,7 +118,7 @@
 (define_constraint "J"
  "A constant that can be used with a SUB operation (once negated)."
  (and (match_code "const_int")
-      (match_test "aarch64_uimm12_shift (-ival)")))
+      (match_test "aarch64_uimm12_shift (- (unsigned HOST_WIDE_INT) ival)")))
 
 ;; We can't use the mode of a CONST_INT to determine the context in
 ;; which it is being used, so we must have a separate constraint for