6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-10-20 09:24:58 +00:00
Code Issues Projects Releases Wiki Activity

Turn (cast (shuffle (cast)) -> shuffle (cast) if it reduces the # casts in

Browse Source 
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
This commit is contained in:
Chris Lattner 2006-05-25 23:24:33 +00:00
parent 8e8a511b58
commit 01575b7315
1 changed files with 31 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -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;
}