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authorNadav Rotem <nrotem@apple.com>2012-12-11 18:58:10 +0000
committerNadav Rotem <nrotem@apple.com>2012-12-11 18:58:10 +0000
commit5e9efa10fc7eea582bb1ad216364fb2c467e4477 (patch)
tree33a68bbe3bbfcb608a9f31cd49d104ed5929e5af /lib
parent37a9830d20018dee5557a3a72f750d965ba383c5 (diff)
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Loop Vectorize: optimize the vectorization of trunc(induction_var). The truncation is now done on scalars.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169904 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r--lib/Transforms/Vectorize/LoopVectorize.cpp14
1 files changed, 13 insertions, 1 deletions
diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index a691240..9550e8a 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1204,8 +1204,20 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
case Instruction::Trunc:
case Instruction::FPTrunc:
case Instruction::BitCast: {
- /// Vectorize bitcasts.
CastInst *CI = dyn_cast<CastInst>(it);
+ /// Optimize the special case where the source is the induction
+ /// variable. Notice that we can only optimize the 'trunc' case
+ /// because: a. FP conversions lose precision, b. sext/zext may wrap,
+ /// c. other casts depend on pointer size.
+ if (CI->getOperand(0) == OldInduction &&
+ it->getOpcode() == Instruction::Trunc) {
+ Value *ScalarCast = Builder.CreateCast(CI->getOpcode(), Induction,
+ CI->getType());
+ Value *Broadcasted = getBroadcastInstrs(ScalarCast);
+ WidenMap[it] = getConsecutiveVector(Broadcasted);
+ break;
+ }
+ /// Vectorize casts.
Value *A = getVectorValue(it->getOperand(0));
Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF);
WidenMap[it] = Builder.CreateCast(CI->getOpcode(), A, DestTy);