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Fix some grammar-os and formatting.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150779 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2012-02-17 02:09:28 +00:00
parent 00195d828b
commit 1bc147b892
1 changed files with 17 additions and 21 deletions
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38
lib/Transforms/Utils/DemoteRegToStack.cpp
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@ -28,7 +28,6 @@ using namespace llvm;
/// alloca. This allows the CFG to be changed around without fear of
/// 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, bool VolatileLoads,
Instruction *AllocaPoint) {
if (I.use_empty()) {
@ -47,20 +46,19 @@ AllocaInst* llvm::DemoteRegToStack(Instruction &I, bool VolatileLoads,
F->getEntryBlock().begin());
}
// Change all of the users of the instruction to read from the stack slot
// instead.
// Change all of the users of the instruction to read from the stack slot.
while (!I.use_empty()) {
Instruction *U = cast<Instruction>(I.use_back());
if (PHINode *PN = dyn_cast<PHINode>(U)) {
// If this is a PHI node, we can't insert a load of the value before the
// use. Instead, insert the load in the predecessor block corresponding
// use. Instead insert the load in the predecessor block corresponding
// to the incoming value.
//
// Note that if there are multiple edges from a basic block to this PHI
// node that we cannot multiple loads. The problem is that the resultant
// PHI node will have multiple values (from each load) coming in from the
// same block, which is illegal SSA form. For this reason, we keep track
// and reuse loads we insert.
// node that we cannot have multiple loads. The problem is that the
// resulting PHI node will have multiple values (from each load) coming in
// from the same block, which is illegal SSA form. For this reason, we
// keep track of and reuse loads we insert.
std::map<BasicBlock*, Value*> Loads;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (PN->getIncomingValue(i) == &I) {
@ -81,9 +79,9 @@ AllocaInst* llvm::DemoteRegToStack(Instruction &I, bool VolatileLoads,
}
// 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.
// Insert stores of the computed value into the stack slot. We have to be
// careful if I is an invoke instruction, because we can't insert the store
// AFTER the terminator instruction.
BasicBlock::iterator InsertPt;
if (!isa<TerminatorInst>(I)) {
InsertPt = &I;
@ -98,16 +96,15 @@ AllocaInst* llvm::DemoteRegToStack(Instruction &I, bool VolatileLoads,
}
for (; isa<PHINode>(InsertPt) || isa<LandingPadInst>(InsertPt); ++InsertPt)
/* empty */; // Don't insert before any PHI nodes or landingpad instrs.
new StoreInst(&I, Slot, InsertPt);
/* empty */; // Don't insert before PHI nodes or landingpad instrs.
new StoreInst(&I, Slot, InsertPt);
return Slot;
}
/// DemotePHIToStack - This function takes a virtual register computed by a phi
/// node and replaces it with a slot in the stack frame, allocated via alloca.
/// The phi node is deleted and it returns the pointer to the alloca inserted.
/// DemotePHIToStack - This function takes a virtual register computed by a PHI
/// node and replaces it with a slot in the stack frame allocated via alloca.
/// The PHI node is deleted. It returns the pointer to the alloca inserted.
AllocaInst* llvm::DemotePHIToStack(PHINode *P, Instruction *AllocaPoint) {
if (P->use_empty()) {
P->eraseFromParent();
@ -125,7 +122,7 @@ AllocaInst* llvm::DemotePHIToStack(PHINode *P, Instruction *AllocaPoint) {
F->getEntryBlock().begin());
}
// Iterate over each operand, insert store in each predecessor.
// Iterate over each operand inserting a store in each predecessor.
for (unsigned i = 0, e = P->getNumIncomingValues(); i < e; ++i) {
if (InvokeInst *II = dyn_cast<InvokeInst>(P->getIncomingValue(i))) {
assert(II->getParent() != P->getIncomingBlock(i) &&
@ -135,12 +132,11 @@ AllocaInst* llvm::DemotePHIToStack(PHINode *P, Instruction *AllocaPoint) {
P->getIncomingBlock(i)->getTerminator());
}
// Insert load in place of the phi and replace all uses.
// Insert a load in place of the PHI and replace all uses.
Value *V = new LoadInst(Slot, P->getName()+".reload", P);
P->replaceAllUsesWith(V);
// Delete phi.
// Delete PHI.
P->eraseFromParent();
return Slot;
}