[llvm-commits] [llvm] r43055 - /llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Devang Patel
dpatel at apple.com
Tue Oct 16 16:44:18 PDT 2007
Author: dpatel
Date: Tue Oct 16 18:44:18 2007
New Revision: 43055
URL: http://llvm.org/viewvc/llvm-project?rev=43055&view=rev
Log:
Use immediate stores.
Modified:
llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=43055&r1=43054&r2=43055&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Tue Oct 16 18:44:18 2007
@@ -7673,18 +7673,40 @@
unsigned Size = MemOpLength->getZExtValue();
unsigned Align = cast<ConstantInt>(CI.getOperand(4))->getZExtValue();
PointerType *NewPtrTy = NULL;
+ unsigned numBits = Size << 3;
// Destination pointer type is always i8 *
// If Size is 8 then use Int64Ty
// If Size is 4 then use Int32Ty
// If Size is 2 then use Int16Ty
// If Size is 1 then use Int8Ty
if (Size && Size <=8 && !(Size&(Size-1)))
- NewPtrTy = PointerType::get(IntegerType::get(Size<<3));
+ NewPtrTy = PointerType::get(IntegerType::get(numBits));
if (NewPtrTy) {
- Value *Src = InsertCastBefore(Instruction::BitCast, CI.getOperand(2), NewPtrTy, CI);
+ Value *L = NULL;
+ // If source is a null terminated constant c string then try to use immediate store.
+ if (Constant *C = dyn_cast<Constant>(CI.getOperand(2))) {
+ const std::string &Str = C->getStringValue();
+ if (!Str.empty()) {
+ APInt StrVal(numBits, 0);
+ unsigned len = Str.length();
+ APInt SingleChar(numBits, 0);
+ for (unsigned i = 0; i < len; i++) {
+ SingleChar = (uint64_t) Str[i];
+ StrVal = (StrVal << 8) | SingleChar;
+ }
+ // Append NULL at the end.
+ SingleChar = 0;
+ StrVal = (StrVal << 8) | SingleChar;
+ L = ConstantInt::get(StrVal);
+ }
+ }
+ // Otherwise load source from memory.
+ if (L == NULL) {
+ Value *Src = InsertCastBefore(Instruction::BitCast, CI.getOperand(2), NewPtrTy, CI);
+ L = new LoadInst(Src, "tmp", false, Align, &CI);
+ }
Value *Dest = InsertCastBefore(Instruction::BitCast, CI.getOperand(1), NewPtrTy, CI);
- Value *L = new LoadInst(Src, "tmp", false, Align, &CI);
Value *NS = new StoreInst(L, Dest, false, Align, &CI);
CI.replaceAllUsesWith(NS);
Changed = true;
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