diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 10 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll | 12 |
2 files changed, 14 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 6252e5d15a1..db5095b6fea 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1128,6 +1128,16 @@ static Value *foldUnsignedUnderflowCheck(ICmpInst *ZeroICmp, EqPred == ICmpInst::ICMP_EQ && !IsAnd) return Builder.CreateICmpULE(Base, Offset); + // Base <= Offset && (Base - Offset) != 0 --> Base < Offset + if (UnsignedPred == ICmpInst::ICMP_ULE && EqPred == ICmpInst::ICMP_NE && + IsAnd) + return Builder.CreateICmpULT(Base, Offset); + + // Base > Offset || (Base - Offset) == 0 --> Base >= Offset + if (UnsignedPred == ICmpInst::ICMP_UGT && EqPred == ICmpInst::ICMP_EQ && + !IsAnd) + return Builder.CreateICmpUGE(Base, Offset); + return nullptr; } diff --git a/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll b/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll index ad60ad98788..d46da5ec863 100644 --- a/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll +++ b/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll @@ -404,10 +404,8 @@ define i1 @base_ult_offset(i8 %base, i8 %offset) { ; CHECK-LABEL: @base_ult_offset( ; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) -; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 -; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ule i8 [[BASE]], [[OFFSET]] -; CHECK-NEXT: [[R:%.*]] = and i1 [[NO_UNDERFLOW]], [[NOT_NULL]] -; CHECK-NEXT: ret i1 [[R]] +; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i8 [[BASE]], [[OFFSET]] +; CHECK-NEXT: ret i1 [[TMP1]] ; %adjusted = sub i8 %base, %offset call void @use8(i8 %adjusted) @@ -420,10 +418,8 @@ define i1 @base_uge_offset(i8 %base, i8 %offset) { ; CHECK-LABEL: @base_uge_offset( ; CHECK-NEXT: [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) -; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0 -; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ugt i8 [[BASE]], [[OFFSET]] -; CHECK-NEXT: [[R:%.*]] = or i1 [[NO_UNDERFLOW]], [[NOT_NULL]] -; CHECK-NEXT: ret i1 [[R]] +; CHECK-NEXT: [[TMP1:%.*]] = icmp uge i8 [[BASE]], [[OFFSET]] +; CHECK-NEXT: ret i1 [[TMP1]] ; %adjusted = sub i8 %base, %offset call void @use8(i8 %adjusted) |
