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author | Chris Lattner <sabre@nondot.org> | 2009-10-11 23:02:46 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2009-10-11 23:02:46 +0000 |
commit | 89f19d1b3a3da269ee5267eab8dad7c07def855b (patch) | |
tree | 20ad46163d7e85a2ed57b52d0af7cef95cb01bed /lib | |
parent | 0505cb155a108d6b9ad4c7866be5d012d2f46181 (diff) | |
download | external_llvm-89f19d1b3a3da269ee5267eab8dad7c07def855b.zip external_llvm-89f19d1b3a3da269ee5267eab8dad7c07def855b.tar.gz external_llvm-89f19d1b3a3da269ee5267eab8dad7c07def855b.tar.bz2 |
remove some harmful code that would turn an insertelement on an undef
into a shuffle even if it was used by another insertelement. If the
visitation order of instcombine was wrong, this would turn a chain of
insertelements into a chain of shufflevectors, which was quite painful.
Since CollectShuffleElements handles these cases, the code can just
be nuked.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83810 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 22 |
1 files changed, 0 insertions, 22 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index dcb65a8..0c790f6 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -12472,28 +12472,6 @@ Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) { if (EI->getOperand(0) == VecOp && ExtractedIdx == InsertedIdx) return ReplaceInstUsesWith(IE, VecOp); - // We could theoretically do this for ANY input. However, doing so could - // turn chains of insertelement instructions into a chain of shufflevector - // instructions, and right now we do not merge shufflevectors. As such, - // only do this in a situation where it is clear that there is benefit. - if (isa<UndefValue>(VecOp) || isa<ConstantAggregateZero>(VecOp)) { - // Turn this into shuffle(EIOp0, VecOp, Mask). The result has all of - // the values of VecOp, except then one read from EIOp0. - // Build a new shuffle mask. - std::vector<Constant*> Mask; - if (isa<UndefValue>(VecOp)) - Mask.assign(NumVectorElts, UndefValue::get(Type::getInt32Ty(*Context))); - else { - assert(isa<ConstantAggregateZero>(VecOp) && "Unknown thing"); - Mask.assign(NumVectorElts, ConstantInt::get(Type::getInt32Ty(*Context), - NumVectorElts)); - } - Mask[InsertedIdx] = - ConstantInt::get(Type::getInt32Ty(*Context), ExtractedIdx); - return new ShuffleVectorInst(EI->getOperand(0), VecOp, - ConstantVector::get(Mask)); - } - // If this insertelement isn't used by some other insertelement, turn it // (and any insertelements it points to), into one big shuffle. if (!IE.hasOneUse() || !isa<InsertElementInst>(IE.use_back())) { |