[llvm-branch-commits] [clang] 99777ef - [X86] Ensure the _mm_test_all_ones macro does not reuse argument (PR60006)

[Tobias Hieta via llvm-branch-commits]

Author: Simon Pilgrim
Date: 2023-01-27T15:28:00+01:00
New Revision: 99777ef91870f8b26cefebd03f26e2052d0e0535

URL: https://github.com/llvm/llvm-project/commit/99777ef91870f8b26cefebd03f26e2052d0e0535
DIFF: https://github.com/llvm/llvm-project/commit/99777ef91870f8b26cefebd03f26e2052d0e0535.diff

LOG: [X86] Ensure the _mm_test_all_ones macro does not reuse argument (PR60006)

The macro _mm_test_all_ones(V) was defined as _mm_testc_si128((V), _mm_cmpeq_epi32((V), (V))) - which could cause side effects depending on the source of the V value.

The _mm_cmpeq_epi32((V), (V)) trick was just to materialize an all-ones value, which can be more safely generated with _mm_set1_epi32(-1) .

Fixes #60006

Differential Revision: https://reviews.llvm.org/D142477

(cherry picked from commit c9b28233599a753506687f2f8a4f96331cd5dbb2)

Added: 
    

Modified: 
    clang/lib/Headers/smmintrin.h
    clang/test/CodeGen/X86/sse41-builtins.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Headers/smmintrin.h b/clang/lib/Headers/smmintrin.h
index 2111c24f31a60..16d8855a1c0b5 100644
--- a/clang/lib/Headers/smmintrin.h
+++ b/clang/lib/Headers/smmintrin.h
@@ -1145,7 +1145,7 @@ static __inline__ int __DEFAULT_FN_ATTRS _mm_testnzc_si128(__m128i __M,
 ///    A 128-bit integer vector containing the bits to be tested.
 /// \returns TRUE if the bits specified in the operand are all set to 1; FALSE
 ///    otherwise.
-#define _mm_test_all_ones(V) _mm_testc_si128((V), _mm_cmpeq_epi32((V), (V)))
+#define _mm_test_all_ones(V) _mm_testc_si128((V), _mm_set1_epi32(-1))
 
 /// Tests whether the specified bits in a 128-bit integer vector are
 ///    neither all zeros nor all ones.

diff  --git a/clang/test/CodeGen/X86/sse41-builtins.c b/clang/test/CodeGen/X86/sse41-builtins.c
index 8573960babb7b..fe59cbcaf1938 100644
--- a/clang/test/CodeGen/X86/sse41-builtins.c
+++ b/clang/test/CodeGen/X86/sse41-builtins.c
@@ -401,3 +401,13 @@ float pr51324(__m128 a) {
   // CHECK: extractelement <4 x float> %{{.*}}, i32 0
   return _mm_round_ps(a, 0)[0];
 }
+
+// Ensure _mm_test_all_ones macro doesn't reuse argument
+__m128i expensive_call();
+int pr60006() {
+  // CHECK-LABEL: pr60006
+  // CHECK: call {{.*}} @expensive_call
+  // CHECK-NOT: call {{.*}} @expensive_call
+  // CHECK: call i32 @llvm.x86.sse41.ptestc(<2 x i64> %{{.*}}, <2 x i64> %{{.*}})
+  return _mm_test_all_ones(expensive_call());
+}