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[committed] i386: Wrong code with __builtin_parityl [PR112672]

Message ID CAFULd4YEFmz9qan3nDMzDE33Y=ioBN94x-C_R=0eYzB8kZQEkQ@mail.gmail.com
State New
Headers show
Series [committed] i386: Wrong code with __builtin_parityl [PR112672] | expand

Commit Message

Uros Bizjak Nov. 23, 2023, 3:23 p.m. UTC 
gen_parityhi2_cmp instruction clobbers its input operand, so use
a temporary register in the call to gen_parityhi2_cmp.

    PR target/112672

gcc/ChangeLog:

    * config/i386/i386.md (parityhi2):
    Use temporary register in the call to gen_parityhi2_cmp.

gcc/testsuite/ChangeLog:

    * gcc.target/i386/pr112672.c: New test.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Uros.
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Patch

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 99bb909b244..41de9537a40 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -20031,8 +20031,10 @@  (define_expand "parityhi2"
   "! TARGET_POPCNT"
 {
   rtx scratch = gen_reg_rtx (QImode);
+  rtx tmp = gen_reg_rtx (HImode);
 
-  emit_insn (gen_parityhi2_cmp (operands[1]));
+  emit_move_insn (tmp, operands[1]);
+  emit_insn (gen_parityhi2_cmp (tmp));
 
   ix86_expand_setcc (scratch, ORDERED,
 		     gen_rtx_REG (CCmode, FLAGS_REG), const0_rtx);
diff --git a/gcc/testsuite/gcc.target/i386/pr112672.c b/gcc/testsuite/gcc.target/i386/pr112672.c
new file mode 100644
index 00000000000..583e9fdfb8b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr112672.c
@@ -0,0 +1,23 @@ 
+/* PR target/112672 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+typedef unsigned short u16;
+
+u16 g = 254;
+
+static inline u16
+foo (u16 u)
+{
+  u *= g;
+  return u + __builtin_parityl (u);
+}
+
+int
+main (void)
+{
+  u16 x = foo (4);
+  if (x != 4 * 254 + 1)
+    __builtin_abort ();
+  return 0;
+}