[InstSimplify] simplifyUnsignedRangeCheck(): X >= Y && Y == 0 --> Y == 0
https://rise4fun.com/Alive/v9Y4
llvm-svn: 372491
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 5c8bf8f..67b06ea 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1443,11 +1443,10 @@
isKnownNonZero(X, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT))
return IsAnd ? UnsignedICmp : ZeroICmp;
- // X >= Y && Y == 0 --> Y == 0 FIXME
+ // X >= Y && Y == 0 --> Y == 0
// X >= Y || Y == 0 --> X >= Y
- if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_EQ &&
- !IsAnd)
- return UnsignedICmp;
+ if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_EQ)
+ return IsAnd ? ZeroICmp : UnsignedICmp;
// X > Y && Y == 0 --> Y == 0 iff X != 0
// X > Y || Y == 0 --> X > Y iff X != 0
diff --git a/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll b/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll
index d30fee9..e0c3a7c 100644
--- a/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll
+++ b/llvm/test/Transforms/InstSimplify/unsigned-range-checks.ll
@@ -84,9 +84,7 @@
define i1 @t8(i8 %x, i8 %y) {
; CHECK-LABEL: @t8(
; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp eq i8 [[Y:%.*]], 0
-; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[Y]], [[X:%.*]]
-; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
-; CHECK-NEXT: ret i1 [[R]]
+; CHECK-NEXT: ret i1 [[NOT_NULL]]
;
%not_null = icmp eq i8 %y, 0
%no_underflow = icmp ule i8 %y, %x