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author | Chris Lattner <sabre@nondot.org> | 2006-05-25 23:24:33 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2006-05-25 23:24:33 +0000 |
commit | 01575b73151e7df62075cc0e5eed656f5ca5c088 (patch) | |
tree | ad7f23e032fa0e23a2f3b4a90c4cc948de6531e8 /lib/Transforms | |
parent | 8e8a511b580a9f620cbe87efa4f8e64affdfa186 (diff) | |
download | llvm-01575b73151e7df62075cc0e5eed656f5ca5c088.tar.gz llvm-01575b73151e7df62075cc0e5eed656f5ca5c088.tar.bz2 llvm-01575b73151e7df62075cc0e5eed656f5ca5c088.tar.xz |
Turn (cast (shuffle (cast)) -> shuffle (cast) if it reduces the # casts in
the program. This exposes more opportunities for the instcombiner, and implements
vec_shuffle.ll:test6
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28487 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
-rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 8bb23226e4..3d096eeecd 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -413,7 +413,7 @@ static bool ValueRequiresCast(const Value *V, const Type *Ty, TargetData *TD) { if (V->getType()->isLosslesslyConvertibleTo(Ty)) return false; - // If this is another cast that can be elimianted, it isn't codegen either. + // If this is another cast that can be eliminated, it isn't codegen either. if (const CastInst *CI = dyn_cast<CastInst>(V)) if (isEliminableCastOfCast(CI->getOperand(0)->getType(), CI->getType(), Ty, TD)) @@ -4970,7 +4970,7 @@ Instruction *InstCombiner::visitCastInst(CastInst &CI) { // If the source value is an instruction with only this use, we can attempt to // propagate the cast into the instruction. Also, only handle integral types // for now. - if (Instruction *SrcI = dyn_cast<Instruction>(Src)) + if (Instruction *SrcI = dyn_cast<Instruction>(Src)) { if (SrcI->hasOneUse() && Src->getType()->isIntegral() && CI.getType()->isInteger()) { // Don't mess with casts to bool here @@ -5152,6 +5152,35 @@ Instruction *InstCombiner::visitCastInst(CastInst &CI) { break; } } + + if (SrcI->hasOneUse()) { + if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(SrcI)) { + // Okay, we have (cast (shuffle ..)). We know this cast is a bitconvert + // because the inputs are known to be a vector. Check to see if this is + // a cast to a vector with the same # elts. + if (isa<PackedType>(CI.getType()) && + cast<PackedType>(CI.getType())->getNumElements() == + SVI->getType()->getNumElements()) { + CastInst *Tmp; + // If either of the operands is a cast from CI.getType(), then + // evaluating the shuffle in the casted destination's type will allow + // us to eliminate at least one cast. + if (((Tmp = dyn_cast<CastInst>(SVI->getOperand(0))) && + Tmp->getOperand(0)->getType() == CI.getType()) || + ((Tmp = dyn_cast<CastInst>(SVI->getOperand(1))) && + Tmp->getOperand(1)->getType() == CI.getType())) { + Value *LHS = InsertOperandCastBefore(SVI->getOperand(0), + CI.getType(), &CI); + Value *RHS = InsertOperandCastBefore(SVI->getOperand(1), + CI.getType(), &CI); + // Return a new shuffle vector. Use the same element ID's, as we + // know the vector types match #elts. + return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2)); + } + } + } + } + } return 0; } |