diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 79 |
1 files changed, 33 insertions, 46 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index b81df12b4c6..257186f4599 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -718,7 +718,7 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op, SCEVHandle BECount = getBackedgeTakenCount(AR->getLoop()); if (!isa<SCEVCouldNotCompute>(BECount)) { // Manually compute the final value for AR, checking for - // overflow at each step. + // overflow. SCEVHandle Start = AR->getStart(); SCEVHandle Step = AR->getStepRecurrence(*this); @@ -730,41 +730,34 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op, getTruncateOrZeroExtend(CastedBECount, BECount->getType())) { const Type *WideTy = IntegerType::get(getTypeSizeInBits(Start->getType()) * 2); + // Check whether Start+Step*BECount has no unsigned overflow. SCEVHandle ZMul = getMulExpr(CastedBECount, getTruncateOrZeroExtend(Step, Start->getType())); - // Check whether Start+Step*BECount has no unsigned overflow. - if (getZeroExtendExpr(ZMul, WideTy) == - getMulExpr(getZeroExtendExpr(CastedBECount, WideTy), - getZeroExtendExpr(Step, WideTy))) { - SCEVHandle Add = getAddExpr(Start, ZMul); - if (getZeroExtendExpr(Add, WideTy) == - getAddExpr(getZeroExtendExpr(Start, WideTy), - getZeroExtendExpr(ZMul, WideTy))) - // Return the expression with the addrec on the outside. - return getAddRecExpr(getZeroExtendExpr(Start, Ty), - getZeroExtendExpr(Step, Ty), - AR->getLoop()); - } + SCEVHandle Add = getAddExpr(Start, ZMul); + if (getZeroExtendExpr(Add, WideTy) == + getAddExpr(getZeroExtendExpr(Start, WideTy), + getMulExpr(getZeroExtendExpr(CastedBECount, WideTy), + getZeroExtendExpr(Step, WideTy)))) + // Return the expression with the addrec on the outside. + return getAddRecExpr(getZeroExtendExpr(Start, Ty), + getZeroExtendExpr(Step, Ty), + AR->getLoop()); // Similar to above, only this time treat the step value as signed. // This covers loops that count down. SCEVHandle SMul = getMulExpr(CastedBECount, getTruncateOrSignExtend(Step, Start->getType())); - // Check whether Start+Step*BECount has no unsigned overflow. - if (getSignExtendExpr(SMul, WideTy) == - getMulExpr(getZeroExtendExpr(CastedBECount, WideTy), - getSignExtendExpr(Step, WideTy))) { - SCEVHandle Add = getAddExpr(Start, SMul); - if (getZeroExtendExpr(Add, WideTy) == - getAddExpr(getZeroExtendExpr(Start, WideTy), - getSignExtendExpr(SMul, WideTy))) - // Return the expression with the addrec on the outside. - return getAddRecExpr(getZeroExtendExpr(Start, Ty), - getSignExtendExpr(Step, Ty), - AR->getLoop()); - } + Add = getAddExpr(Start, SMul); + if (getZeroExtendExpr(Add, WideTy) == + getAddExpr(getZeroExtendExpr(Start, WideTy), + getMulExpr(getZeroExtendExpr(CastedBECount, WideTy), + getSignExtendExpr(Step, WideTy)))) + // Return the expression with the addrec on the outside. + return getAddRecExpr(getZeroExtendExpr(Start, Ty), + getSignExtendExpr(Step, Ty), + AR->getLoop()); } } } @@ -807,37 +800,31 @@ SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op, SCEVHandle BECount = getBackedgeTakenCount(AR->getLoop()); if (!isa<SCEVCouldNotCompute>(BECount)) { // Manually compute the final value for AR, checking for - // overflow at each step. + // overflow. SCEVHandle Start = AR->getStart(); SCEVHandle Step = AR->getStepRecurrence(*this); // Check whether the backedge-taken count can be losslessly casted to - // the addrec's type. The count needs to be the same whether sign - // extended or zero extended. + // the addrec's type. The count is always unsigned. SCEVHandle CastedBECount = getTruncateOrZeroExtend(BECount, Start->getType()); if (BECount == - getTruncateOrZeroExtend(CastedBECount, BECount->getType()) && - BECount == - getTruncateOrSignExtend(CastedBECount, BECount->getType())) { + getTruncateOrZeroExtend(CastedBECount, BECount->getType())) { const Type *WideTy = IntegerType::get(getTypeSizeInBits(Start->getType()) * 2); + // Check whether Start+Step*BECount has no signed overflow. SCEVHandle SMul = getMulExpr(CastedBECount, getTruncateOrSignExtend(Step, Start->getType())); - // Check whether Start+Step*BECount has no signed overflow. - if (getSignExtendExpr(SMul, WideTy) == - getMulExpr(getSignExtendExpr(CastedBECount, WideTy), - getSignExtendExpr(Step, WideTy))) { - SCEVHandle Add = getAddExpr(Start, SMul); - if (getSignExtendExpr(Add, WideTy) == - getAddExpr(getSignExtendExpr(Start, WideTy), - getSignExtendExpr(SMul, WideTy))) - // Return the expression with the addrec on the outside. - return getAddRecExpr(getSignExtendExpr(Start, Ty), - getSignExtendExpr(Step, Ty), - AR->getLoop()); - } + SCEVHandle Add = getAddExpr(Start, SMul); + if (getSignExtendExpr(Add, WideTy) == + getAddExpr(getSignExtendExpr(Start, WideTy), + getMulExpr(getZeroExtendExpr(CastedBECount, WideTy), + getSignExtendExpr(Step, WideTy)))) + // Return the expression with the addrec on the outside. + return getAddRecExpr(getSignExtendExpr(Start, Ty), + getSignExtendExpr(Step, Ty), + AR->getLoop()); } } } |
