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Transform calls to memcpy into llvm.memcpy calls, patch by Eli Friedman.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46433 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-01-28 04:41:43 +00:00
parent 2671fc390c
commit 0818ea8317
1 changed files with 30 additions and 0 deletions
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30
lib/Transforms/IPO/SimplifyLibCalls.cpp
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@ -919,6 +919,36 @@ struct VISIBILITY_HIDDEN memcmpOptimization : public LibCallOptimization {
}
} memcmpOptimizer;
/// This LibCallOptimization will simplify a call to the memcpy library
/// function. It simply converts them into calls to llvm.memcpy.*;
/// the resulting call should be optimized later.
/// @brief Simplify the memcpy library function.
struct VISIBILITY_HIDDEN MemCpyOptimization : public LibCallOptimization {
public:
MemCpyOptimization() : LibCallOptimization("memcpy",
"Number of 'memcpy' calls simplified") {}
/// @brief Make sure that the "memcpy" function has the right prototype
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
const FunctionType *FT = F->getFunctionType();
const Type* voidPtr = PointerType::getUnqual(Type::Int8Ty);
return FT->getReturnType() == voidPtr && FT->getNumParams() == 3 &&
FT->getParamType(0) == voidPtr &&
FT->getParamType(1) == voidPtr &&
FT->getParamType(2) == SLC.getIntPtrType();
}
/// @brief Perform the memcpy optimization
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
Value *MemcpyOps[] = {
CI->getOperand(1), CI->getOperand(2), CI->getOperand(3),
ConstantInt::get(Type::Int32Ty, 1) // align = 1 always.
};
new CallInst(SLC.get_memcpy(), MemcpyOps, MemcpyOps + 4, "", CI);
// memcpy always returns the destination
return ReplaceCallWith(CI, CI->getOperand(1));
}
} MemCpyOptimizer;
/// This LibCallOptimization will simplify a call to the memcpy library
/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8