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-rw-r--r--llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll15
1 files changed, 15 insertions, 0 deletions
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll b/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
index 4661106a89e..5107e833ecf 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
@@ -281,6 +281,21 @@ define i1 @usubo_eq_constant1_op1_i32(i32 %x, i32* %p) {
ret i1 %ov
}
+; Special-case: subtract from 0 (negate) changes the compare predicate.
+
+define i1 @usubo_ne_constant0_op1_i32(i32 %x, i32* %p) {
+; CHECK-LABEL: @usubo_ne_constant0_op1_i32(
+; CHECK-NEXT: [[S:%.*]] = sub i32 0, [[X:%.*]]
+; CHECK-NEXT: [[OV:%.*]] = icmp ne i32 [[X]], 0
+; CHECK-NEXT: store i32 [[S]], i32* [[P:%.*]]
+; CHECK-NEXT: ret i1 [[OV]]
+;
+ %s = sub i32 0, %x
+ %ov = icmp ne i32 %x, 0
+ store i32 %s, i32* %p
+ ret i1 %ov
+}
+
; Verify insertion point for multi-BB.
declare void @call(i1)
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