From fc984e9c0ccb001c4865b0f16c6364d74a863cf4 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 29 Apr 2008 17:13:43 +0000 Subject: fix a subtle volatile handling bug. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50428 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/InstructionCombining.cpp | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'lib/Transforms/Scalar') diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index c707e6e..86aca07 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -9432,16 +9432,21 @@ Instruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { // Insert and return the new operation. if (CastInst* FirstCI = dyn_cast(FirstInst)) return CastInst::create(FirstCI->getOpcode(), PhiVal, PN.getType()); - else if (isa(FirstInst)) - return new LoadInst(PhiVal, "", isVolatile); - else if (BinaryOperator *BinOp = dyn_cast(FirstInst)) + if (BinaryOperator *BinOp = dyn_cast(FirstInst)) return BinaryOperator::create(BinOp->getOpcode(), PhiVal, ConstantOp); - else if (CmpInst *CIOp = dyn_cast(FirstInst)) + if (CmpInst *CIOp = dyn_cast(FirstInst)) return CmpInst::create(CIOp->getOpcode(), CIOp->getPredicate(), PhiVal, ConstantOp); - else - assert(0 && "Unknown operation"); - return 0; + assert(isa(FirstInst) && "Unknown operation"); + + // If this was a volatile load that we are merging, make sure to loop through + // and mark all the input loads as non-volatile. If we don't do this, we will + // insert a new volatile load and the old ones will not be deletable. + if (isVolatile) + for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) + cast(PN.getIncomingValue(i))->setVolatile(false); + + return new LoadInst(PhiVal, "", isVolatile); } /// DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle -- cgit v1.1