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Cleanup some of my patches from yesterday. Refactor the check for which xform

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to apply to a memcpy into processInstruction.  Also, fix a bug in the check due to
missing braces.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47307 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2008-02-19 03:09:45 +00:00
parent 9103ba1003
commit 7acc0af95a
1 changed files with 23 additions and 22 deletions
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45
lib/Transforms/Scalar/GVN.cpp
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@ -738,7 +738,8 @@ namespace {
SmallVector<Instruction*, 4>& toErase);
bool processNonLocalLoad(LoadInst* L,
SmallVector<Instruction*, 4>& toErase);
bool processMemCpy(MemCpyInst* M, SmallVector<Instruction*, 4>& toErase);
bool processMemCpy(MemCpyInst* M, MemCpyInst* MDep,
SmallVector<Instruction*, 4>& toErase);
bool performReturnSlotOptzn(MemCpyInst* cpy, CallInst* C,
SmallVector<Instruction*, 4>& toErase);
Value *GetValueForBlock(BasicBlock *BB, LoadInst* orig,
@ -1111,24 +1112,10 @@ bool GVN::performReturnSlotOptzn(MemCpyInst* cpy, CallInst* C,
/// copies X to Y, and memcpy B which copies Y to Z, then we can rewrite B to be
/// a memcpy from X to Z (or potentially a memmove, depending on circumstances).
/// This allows later passes to remove the first memcpy altogether.
bool GVN::processMemCpy(MemCpyInst* M,
bool GVN::processMemCpy(MemCpyInst* M, MemCpyInst* MDep,
SmallVector<Instruction*, 4>& toErase) {
MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
// First, we have to check that the dependency is another memcpy
Instruction* dep = MD.getDependency(M);
if (dep == MemoryDependenceAnalysis::None ||
dep == MemoryDependenceAnalysis::NonLocal)
return false;
else if (CallInst* C = dyn_cast<CallInst>(dep))
if (!isa<MemCpyInst>(C))
return performReturnSlotOptzn(M, C, toErase);
else if (!isa<MemCpyInst>(dep))
return false;
// We can only transforms memcpy's where the dest of one is the source of the
// other
MemCpyInst* MDep = cast<MemCpyInst>(dep);
if (M->getSource() != MDep->getDest())
return false;
@ -1159,11 +1146,9 @@ bool GVN::processMemCpy(MemCpyInst* M,
return false;
// If all checks passed, then we can transform these memcpy's
bool is32bit = M->getIntrinsicID() == Intrinsic::memcpy_i32;
Function* MemMoveFun = Intrinsic::getDeclaration(
Function* MemCpyFun = Intrinsic::getDeclaration(
M->getParent()->getParent()->getParent(),
is32bit ? Intrinsic::memcpy_i32 :
Intrinsic::memcpy_i64);
M->getIntrinsicID());
std::vector<Value*> args;
args.push_back(M->getRawDest());
@ -1171,8 +1156,9 @@ bool GVN::processMemCpy(MemCpyInst* M,
args.push_back(M->getLength());
args.push_back(M->getAlignment());
CallInst* C = new CallInst(MemMoveFun, args.begin(), args.end(), "", M);
CallInst* C = new CallInst(MemCpyFun, args.begin(), args.end(), "", M);
MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
if (MD.getDependency(C) == MDep) {
MD.dropInstruction(M);
toErase.push_back(M);
@ -1193,7 +1179,22 @@ bool GVN::processInstruction(Instruction* I,
if (LoadInst* L = dyn_cast<LoadInst>(I)) {
return processLoad(L, lastSeenLoad, toErase);
} else if (MemCpyInst* M = dyn_cast<MemCpyInst>(I)) {
return processMemCpy(M, toErase);
MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
// The are two possible optimizations we can do for memcpy:
// a) memcpy-memcpy xform which exposes redundance for DSE
// b) call-memcpy xform for sret return slot optimization
Instruction* dep = MD.getDependency(M);
if (dep == MemoryDependenceAnalysis::None ||
dep == MemoryDependenceAnalysis::NonLocal)
return false;
else if (CallInst* C = dyn_cast<CallInst>(dep)) {
if (!isa<MemCpyInst>(C))
return performReturnSlotOptzn(M, C, toErase);
} else if (!isa<MemCpyInst>(dep))
return false;
return processMemCpy(M, cast<MemCpyInst>(dep), toErase);
}
unsigned num = VN.lookup_or_add(I);