diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine')
-rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 35 |
1 files changed, 16 insertions, 19 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index d3155e13c4d..a2f7fa3c19a 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1971,15 +1971,6 @@ Instruction *InstCombiner::foldICmpUDivConstant(ICmpInst &Cmp, Instruction *InstCombiner::foldICmpDivConstant(ICmpInst &Cmp, BinaryOperator *Div, const APInt *C) { - // FIXME: These checks restrict all folds under here to scalar types. - ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1)); - if (!RHS) - return nullptr; - - ConstantInt *DivRHS = dyn_cast<ConstantInt>(Div->getOperand(1)); - if (!DivRHS) - return nullptr; - // Fold: icmp pred ([us]div X, C2), C -> range test // Fold this div into the comparison, producing a range check. // Determine, based on the divide type, what the range is being @@ -2002,16 +1993,22 @@ Instruction *InstCombiner::foldICmpDivConstant(ICmpInst &Cmp, if (!Cmp.isEquality() && DivIsSigned != Cmp.isSigned()) return nullptr; - // FIXME: These 3 checks can be asserts. - if (*C2 == 0) - return nullptr; // The ProdOV computation fails on divide by zero. - if (DivIsSigned && C2->isAllOnesValue()) - return nullptr; // The overflow computation also screws up here - if (*C2 == 1) { - // This eliminates some funny cases with INT_MIN. - Cmp.setOperand(0, Div->getOperand(0)); // X/1 == X. - return &Cmp; - } + // These constant divides should already be folded in InstSimplify. + assert(*C2 != 0 && "The ProdOV computation fails on divide by zero."); + assert(*C2 != 1 && "Funny cases with INT_MIN will fail."); + + // This constant divide should already be folded in InstCombine. + assert(!(DivIsSigned && C2->isAllOnesValue()) && + "The overflow computation will fail."); + + // FIXME: These checks restrict all folds under here to scalar types. + ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1)); + if (!RHS) + return nullptr; + + ConstantInt *DivRHS = dyn_cast<ConstantInt>(Div->getOperand(1)); + if (!DivRHS) + return nullptr; // Compute Prod = CI * DivRHS. We are essentially solving an equation // of form X/C2=C. We solve for X by multiplying C2 (DivRHS) and |