instcombine: Migrate memset optimizations
This patch migrates the memset optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167689 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index b4dc93d..c3ea638 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -997,6 +997,25 @@
}
};
+struct MemSetOpt : public LibCallOptimization {
+ virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // These optimizations require DataLayout.
+ if (!TD) return 0;
+
+ FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
+ !FT->getParamType(0)->isPointerTy() ||
+ !FT->getParamType(1)->isIntegerTy() ||
+ FT->getParamType(2) != TD->getIntPtrType(*Context))
+ return 0;
+
+ // memset(p, v, n) -> llvm.memset(p, v, n, 1)
+ Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
+ B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
+ return CI->getArgOperand(0);
+ }
+};
+
} // End anonymous namespace.
namespace llvm {
@@ -1036,6 +1055,7 @@
MemCmpOpt MemCmp;
MemCpyOpt MemCpy;
MemMoveOpt MemMove;
+ MemSetOpt MemSet;
void initOptimizations();
void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
@@ -1087,6 +1107,7 @@
addOpt(LibFunc::memcmp, &MemCmp);
addOpt(LibFunc::memcpy, &MemCpy);
addOpt(LibFunc::memmove, &MemMove);
+ addOpt(LibFunc::memset, &MemSet);
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {