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tidy interface to isOnlyCopiedFromConstantGlobal

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101405 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-04-15 21:59:20 +00:00
parent 51faa37b4e
commit 31d80103d5
1 changed files with 14 additions and 15 deletions
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29
lib/Transforms/Scalar/ScalarReplAggregates.cpp
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@ -137,7 +137,7 @@ namespace {
uint64_t Offset, IRBuilder<> &Builder);
Value *ConvertScalar_InsertValue(Value *StoredVal, Value *ExistingVal,
uint64_t Offset, IRBuilder<> &Builder);
static Instruction *isOnlyCopiedFromConstantGlobal(AllocaInst *AI);
static MemTransferInst *isOnlyCopiedFromConstantGlobal(AllocaInst *AI);
};
}
@ -223,7 +223,7 @@ static bool ShouldAttemptScalarRepl(AllocaInst *AI) {
bool SROA::performScalarRepl(Function &F) {
std::vector<AllocaInst*> WorkList;
// Scan the entry basic block, adding any alloca's and mallocs to the worklist
// Scan the entry basic block, adding allocas to the worklist.
BasicBlock &BB = F.getEntryBlock();
for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
if (AllocaInst *A = dyn_cast<AllocaInst>(I))
@ -251,10 +251,10 @@ bool SROA::performScalarRepl(Function &F) {
// the constant global instead. This is commonly produced by the CFE by
// constructs like "void foo() { int A[] = {1,2,3,4,5,6,7,8,9...}; }" if 'A'
// is only subsequently read.
if (Instruction *TheCopy = isOnlyCopiedFromConstantGlobal(AI)) {
if (MemTransferInst *TheCopy = isOnlyCopiedFromConstantGlobal(AI)) {
DEBUG(dbgs() << "Found alloca equal to global: " << *AI << '\n');
DEBUG(dbgs() << " memcpy = " << *TheCopy << '\n');
Constant *TheSrc = cast<Constant>(TheCopy->getOperand(1));
Constant *TheSrc = cast<Constant>(TheCopy->getSource());
AI->replaceAllUsesWith(ConstantExpr::getBitCast(TheSrc, AI->getType()));
TheCopy->eraseFromParent(); // Don't mutate the global.
AI->eraseFromParent();
@ -271,7 +271,10 @@ bool SROA::performScalarRepl(Function &F) {
// Do not promote [0 x %struct].
if (AllocaSize == 0) continue;
// Do not promote any struct whose size is too big.
if (AllocaSize > SRThreshold) continue;
// If the alloca looks like a good candidate for scalar replacement, and if
// all its users can be transformed, then split up the aggregate into its
// separate elements.
@ -281,9 +284,6 @@ bool SROA::performScalarRepl(Function &F) {
continue;
}
// Do not promote any struct whose size is too big.
if (AllocaSize > SRThreshold) continue;
// If we can turn this aggregate value (potentially with casts) into a
// simple scalar value that can be mem2reg'd into a register value.
// IsNotTrivial tracks whether this is something that mem2reg could have
@ -1699,7 +1699,7 @@ static bool PointsToConstantGlobal(Value *V) {
/// the uses. If we see a memcpy/memmove that targets an unoffseted pointer to
/// the alloca, and if the source pointer is a pointer to a constant global, we
/// can optimize this.
static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
static bool isOnlyCopiedFromConstantGlobal(Value *V, MemTransferInst *&TheCopy,
bool isOffset) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI!=E; ++UI) {
User *U = cast<Instruction>(*UI);
@ -1726,7 +1726,8 @@ static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
// If this is isn't our memcpy/memmove, reject it as something we can't
// handle.
if (!isa<MemTransferInst>(U))
MemTransferInst *MI = dyn_cast<MemTransferInst>(U);
if (MI == 0)
return false;
// If we already have seen a copy, reject the second one.
@ -1739,10 +1740,8 @@ static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
// If the memintrinsic isn't using the alloca as the dest, reject it.
if (UI.getOperandNo() != 0) return false;
MemIntrinsic *MI = cast<MemIntrinsic>(U);
// If the source of the memcpy/move is not a constant global, reject it.
if (!PointsToConstantGlobal(MI->getOperand(1)))
if (!PointsToConstantGlobal(MI->getSource()))
return false;
// Otherwise, the transform is safe. Remember the copy instruction.
@ -1754,8 +1753,8 @@ static bool isOnlyCopiedFromConstantGlobal(Value *V, Instruction *&TheCopy,
/// isOnlyCopiedFromConstantGlobal - Return true if the specified alloca is only
/// modified by a copy from a constant global. If we can prove this, we can
/// replace any uses of the alloca with uses of the global directly.
Instruction *SROA::isOnlyCopiedFromConstantGlobal(AllocaInst *AI) {
Instruction *TheCopy = 0;
MemTransferInst *SROA::isOnlyCopiedFromConstantGlobal(AllocaInst *AI) {
MemTransferInst *TheCopy = 0;
if (::isOnlyCopiedFromConstantGlobal(AI, TheCopy, false))
return TheCopy;
return 0;