diff mbox series

middle-end/106053 - fold_sign_changed_comparison and large bools

Message ID 20220628100106.BA91E38356AA@sourceware.org
State Committed
Commit a3ca1fc5f409e257e9fb9a8165bb4a7068ddebbe
Headers
Series middle-end/106053 - fold_sign_changed_comparison and large bools |

Commit Message

Richard Biener June 28, 2022, 10 a.m. UTC 
  The following fixes a latent issue in the match.pd variant of
fold_sign_changed_comparison which replaces an unsigned integer
comparison with a signed boolean comparison of the same precision
despite the fact that we treat BOOLEAN_TYPEs as only having two
valid values.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed to trunk
sofar.

2022-06-28  Richard Biener  <rguenther@suse.de>

	PR middle-end/106053
	* match.pd ((T)a == (T)b): Avoid folding away sign
	changes in a comparison if we'd truncate to a boolean.

	* gcc.target/i386/pr106053.c: New testcase.
---
 gcc/match.pd                             |  7 ++++-
 gcc/testsuite/gcc.target/i386/pr106053.c | 37 ++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr106053.c
diff mbox series

Patch

diff --git a/gcc/match.pd b/gcc/match.pd
index 24cbbbb5bc1..c43c528424e 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5542,7 +5542,12 @@  DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	&& (TYPE_UNSIGNED (TREE_TYPE (@00)) == TYPE_UNSIGNED (TREE_TYPE (@0))
 	    || cmp == NE_EXPR
 	    || cmp == EQ_EXPR)
-	&& !POINTER_TYPE_P (TREE_TYPE (@00)))
+	&& !POINTER_TYPE_P (TREE_TYPE (@00))
+	/* (int)bool:32 != (int)uint is not the same as
+	   bool:32 != (bool:32)uint since boolean types only have two valid
+	   values independent of their precision.  */
+	&& (TREE_CODE (TREE_TYPE (@00)) != BOOLEAN_TYPE
+	    || TREE_CODE (TREE_TYPE (@10)) == BOOLEAN_TYPE))
     /* ???  The special-casing of INTEGER_CST conversion was in the original
        code and here to avoid a spurious overflow flag on the resulting
        constant which fold_convert produces.  */
diff --git a/gcc/testsuite/gcc.target/i386/pr106053.c b/gcc/testsuite/gcc.target/i386/pr106053.c
new file mode 100644
index 00000000000..69baa3e5fd1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr106053.c
@@ -0,0 +1,37 @@ 
+/* { dg-do run { target lp64 } } */
+/* { dg-options "-O -fno-tree-fre -w -mno-avx" } */
+
+typedef unsigned __attribute__((__vector_size__ (32))) v256u8;
+typedef unsigned __attribute__((__vector_size__ (64))) v512u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+typedef unsigned long long u64;
+typedef unsigned long __attribute__((__vector_size__ (64))) v512u64;
+typedef unsigned __int128 __attribute__((__vector_size__ (32))) v256u128;
+unsigned u;
+v512u64 foo0_v512u64_0;
+
+static inline v256u8
+foo (u32 u32_0, u64 u64_0, v256u128 v256u128_0)
+{
+  int o = __builtin_add_overflow_p (u64_0, 0, 0);
+  v512u64 v512u64_1 =
+    foo0_v512u64_0 & (u32) __builtin_sub_overflow_p (0, o, 0);
+  u64_0 |= u;
+  v256u128 v256u128_2 = u64_0 < v256u128_0;
+  v256u128 v256u128_3 = -v256u128_2 == u64_0 * u32_0;
+  v256u8 v256u8_r = ((union {
+                      v512u8 a; v256u8 b[2];
+                      }) (v512u8) v512u64_1).b[0] + (v256u8) v256u128_3;
+  return v256u8_r;
+}
+
+int
+main (void)
+{
+  v256u8 x = foo (3095179400, 23725760132, (v256u128) { 2, 2 });
+  for (unsigned i = 0; i < sizeof (x) / sizeof (x[0]); i++)
+    if (x[i])
+      __builtin_abort ();
+  return 0;
+}