diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 8 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/div.ll | 18 |
2 files changed, 26 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index a554e9f628e..bb3d9281edb 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -95,6 +95,14 @@ static bool IsMultiple(const APInt &C1, const APInt &C2, APInt &Quotient, assert(C1.getBitWidth() == C2.getBitWidth() && "Inconsistent width of constants!"); + // Bail if we will divide by zero. + if (C2.isMinValue()) + return false; + + // Bail if we would divide INT_MIN by -1. + if (IsSigned && C1.isMinSignedValue() && C2.isAllOnesValue()) + return false; + APInt Remainder(C1.getBitWidth(), /*Val=*/0ULL, IsSigned); if (IsSigned) APInt::sdivrem(C1, C2, Quotient, Remainder); diff --git a/llvm/test/Transforms/InstCombine/div.ll b/llvm/test/Transforms/InstCombine/div.ll index 933d9ec4b0d..3194c015fd7 100644 --- a/llvm/test/Transforms/InstCombine/div.ll +++ b/llvm/test/Transforms/InstCombine/div.ll @@ -325,3 +325,21 @@ define i32 @test36(i32 %A) { ; CHECK-NEXT: %[[shr:.*]] = lshr exact i32 %[[and]], %A ; CHECK-NEXT: ret i32 %[[shr]] } + +define i32 @test37(i32* %b) { +entry: + store i32 0, i32* %b, align 4 + %0 = load i32, i32* %b, align 4 + br i1 undef, label %lor.rhs, label %lor.end + +lor.rhs: ; preds = %entry + %mul = mul nsw i32 undef, %0 + br label %lor.end + +lor.end: ; preds = %lor.rhs, %entry + %t.0 = phi i32 [ %0, %entry ], [ %mul, %lor.rhs ] + %div = sdiv i32 %t.0, 2 + ret i32 %div +; CHECK-LABEL: @test37( +; CHECK: ret i32 0 +} |
