Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.462 -> 1.463
---
Log message:
Implement InstCombine/vec_shuffle.ll:test[12]
---
Diffs of the changes: (+62 -0)
InstructionCombining.cpp | 62 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 62 insertions(+)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.462
llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.463
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.462 Thu Apr 6
14:19:17 2006
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Mon Apr 10 17:45:52 2006
@@ -138,6 +138,7 @@
Instruction *visitBranchInst(BranchInst &BI);
Instruction *visitSwitchInst(SwitchInst &SI);
Instruction *visitExtractElementInst(ExtractElementInst &EI);
+ Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
// visitInstruction - Specify what to return for unhandled instructions...
Instruction *visitInstruction(Instruction &I) { return 0; }
@@ -6876,6 +6877,67 @@
return 0;
}
+Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
+ Value *LHS = SVI.getOperand(0);
+ Value *RHS = SVI.getOperand(1);
+ Constant *Mask = cast<Constant>(SVI.getOperand(2));
+
+ bool MadeChange = false;
+
+ if (isa<UndefValue>(Mask))
+ return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
+
+ // Canonicalize shuffle(x,x) -> shuffle(x,undef)
+ if (LHS == RHS) {
+ if (isa<UndefValue>(LHS)) {
+ // shuffle(undef,undef,mask) -> undef.
+ return ReplaceInstUsesWith(SVI, LHS);
+ }
+
+ if (!isa<ConstantAggregateZero>(Mask)) {
+ // Remap any references to RHS to use LHS.
+ ConstantPacked *CP = cast<ConstantPacked>(Mask);
+ std::vector<Constant*> Elts;
+ for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) {
+ Elts.push_back(CP->getOperand(i));
+ if (isa<UndefValue>(CP->getOperand(i)))
+ continue;
+ unsigned MV = cast<ConstantInt>(CP->getOperand(i))->getRawValue();
+ if (MV >= e)
+ Elts.back() = ConstantUInt::get(Type::UIntTy, MV & (e-1));
+ }
+ Mask = ConstantPacked::get(Elts);
+ }
+ SVI.setOperand(1, UndefValue::get(RHS->getType()));
+ SVI.setOperand(2, Mask);
+ MadeChange = true;
+ }
+
+ if (ConstantPacked *CP = dyn_cast<ConstantPacked>(Mask)) {
+ bool isLHSID = true, isRHSID = true;
+
+ // Analyze the shuffle.
+ for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) {
+ if (isa<UndefValue>(CP->getOperand(i)))
+ continue;
+ unsigned MV = cast<ConstantInt>(CP->getOperand(i))->getRawValue();
+
+ // Is this an identity shuffle of the LHS value?
+ isLHSID &= (MV == i);
+
+ // Is this an identity shuffle of the RHS value?
+ isRHSID &= (MV-e == i);
+ }
+
+ // Eliminate identity shuffles.
+ if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
+ if (isRHSID) return ReplaceInstUsesWith(SVI, RHS);
+ }
+
+ return MadeChange ? &SVI : 0;
+}
+
+
void InstCombiner::removeFromWorkList(Instruction *I) {
WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), I),
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