Hi!
The last case of this optimization assumes that if 2 integral types
have same precision and TYPE_UNSIGNED, then they are uselessly convertible.
While that is very likely the case for GIMPLE, it is not the case for
GENERIC, so the following patch adds there a convert so that the
optimization produces also valid GENERIC. Without it we got
(int) p == b where b had _BitInt(32) type, so incompatible types.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2025-01-17 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/118522
* match.pd ((FTYPE) N CMP (FTYPE) M): Add convert, as in GENERIC
integral types with the same precision and sign might actually not
be compatible types.
* gcc.dg/bitint-120.c: New test.
--- gcc/match.pd.jj 2025-01-16 09:09:06.000000000 +0100
+++ gcc/match.pd 2025-01-16 19:24:16.838305254 +0100
@@ -7253,7 +7253,7 @@ (define_operator_list SYNC_FETCH_AND_AND
(icmp (convert:type2 @1) @2)
(if (TYPE_PRECISION (type1) == TYPE_PRECISION (type2)
&& type1_signed_p == type2_signed_p)
- (icmp @1 @2))))))))))
+ (icmp @1 (convert @2)))))))))))
/* Optimize various special cases of (FTYPE) N CMP CST. */
(for cmp (lt le eq ne ge gt)
--- gcc/testsuite/gcc.dg/bitint-120.c.jj 2025-01-16 19:30:14.816518100
+0100
+++ gcc/testsuite/gcc.dg/bitint-120.c 2025-01-16 19:29:56.429763982 +0100
@@ -0,0 +1,11 @@
+/* PR tree-optimization/118522 */
+/* { dg-do compile { target bitint } } */
+/* { dg-options "-O2" } */
+
+_BitInt(32) b;
+
+int
+foo (unsigned short p)
+{
+ return p == (double) b;
+}
Jakub
