diff options
| -rw-r--r-- | llvm/lib/Transforms/Utils/DemoteRegToStack.cpp | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/llvm/lib/Transforms/Utils/DemoteRegToStack.cpp b/llvm/lib/Transforms/Utils/DemoteRegToStack.cpp index ecd92f7fdb6..bbf998d790c 100644 --- a/llvm/lib/Transforms/Utils/DemoteRegToStack.cpp +++ b/llvm/lib/Transforms/Utils/DemoteRegToStack.cpp @@ -29,7 +29,7 @@ using namespace llvm; /// invalidating the SSA information for the value. It returns the pointer to /// the alloca inserted to create a stack slot for I. /// -AllocaInst* llvm::DemoteRegToStack(Instruction &I) { +AllocaInst* llvm::DemoteRegToStack(Instruction &I, bool VolatileLoads) { if (I.use_empty()) return 0; // nothing to do! // Create a stack slot to hold the value. @@ -57,7 +57,7 @@ AllocaInst* llvm::DemoteRegToStack(Instruction &I) { Value *&V = Loads[PN->getIncomingBlock(i)]; if (V == 0) { // Insert the load into the predecessor block - V = new LoadInst(Slot, I.getName()+".reload", + V = new LoadInst(Slot, I.getName()+".reload", VolatileLoads, PN->getIncomingBlock(i)->getTerminator()); } PN->setIncomingValue(i, V); @@ -65,7 +65,7 @@ AllocaInst* llvm::DemoteRegToStack(Instruction &I) { } else { // If this is a normal instruction, just insert a load. - Value *V = new LoadInst(Slot, I.getName()+".reload", U); + Value *V = new LoadInst(Slot, I.getName()+".reload", VolatileLoads, U); U->replaceUsesOfWith(&I, V); } } @@ -74,18 +74,21 @@ AllocaInst* llvm::DemoteRegToStack(Instruction &I) { // Insert stores of the computed value into the stack slot. We have to be // careful is I is an invoke instruction though, because we can't insert the // store AFTER the terminator instruction. + BasicBlock::iterator InsertPt; if (!isa<TerminatorInst>(I)) { - BasicBlock::iterator InsertPt = &I; - for (++InsertPt; isa<PHINode>(InsertPt); ++InsertPt) - /* empty */; // Don't insert before any PHI nodes. - new StoreInst(&I, Slot, InsertPt); + InsertPt = &I; } else { - // FIXME: We cannot yet demote invoke instructions to the stack, because - // doing so would require breaking critical edges. This should be fixed - // eventually. - assert(0 && - "Cannot demote the value computed by an invoke instruction yet!"); + // We cannot demote invoke instructions to the stack if their normal edge + // is critical. + InvokeInst &II = cast<InvokeInst>(I); + assert(II.getNormalDest()->getSinglePredecessor() && + "Cannot demote invoke with a critical successor!"); + InsertPt = II.getNormalDest()->begin(); } + for (++InsertPt; isa<PHINode>(InsertPt); ++InsertPt) + /* empty */; // Don't insert before any PHI nodes. + new StoreInst(&I, Slot, InsertPt); + return Slot; } |
