From b4d6a5a76cca5828c9e2599f12036c7f9c5f89d7 Mon Sep 17 00:00:00 2001 From: Matthijs Kooijman Date: Wed, 11 Jun 2008 09:00:12 +0000 Subject: Clarify a comment. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52212 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/InstructionCombining.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 3b181c8..a1a3333 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -10613,7 +10613,6 @@ static Value *FindScalarElement(Value *V, unsigned EltNo) { } Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) { - // If vector val is undef, replace extract with scalar undef. if (isa(EI.getOperand(0))) return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType())); @@ -10623,8 +10622,9 @@ Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) { return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType())); if (ConstantVector *C = dyn_cast(EI.getOperand(0))) { - // If vector val is constant with uniform operands, replace EI - // with that operand + // If vector val is constant with all elements the same, replace EI with + // that element. When the elements are not identical, we cannot replace yet + // (we do that below, but only when the index is constant). Constant *op0 = C->getOperand(0); for (unsigned i = 1; i < C->getNumOperands(); ++i) if (C->getOperand(i) != op0) { -- cgit v1.1