[SimplifyLibcalls] Realloc(null, N) -> Malloc(N)
Patch by Dávid Bolvanský!
Differential Revision: https://reviews.llvm.org/D45413
llvm-svn: 330259
diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 6c68b88..e65ecc5 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -811,27 +811,6 @@
return CI->getArgOperand(0);
}
-// TODO: Does this belong in BuildLibCalls or should all of those similar
-// functions be moved here?
-static Value *emitCalloc(Value *Num, Value *Size, const AttributeList &Attrs,
- IRBuilder<> &B, const TargetLibraryInfo &TLI) {
- LibFunc Func;
- if (!TLI.getLibFunc("calloc", Func) || !TLI.has(Func))
- return nullptr;
-
- Module *M = B.GetInsertBlock()->getModule();
- const DataLayout &DL = M->getDataLayout();
- IntegerType *PtrType = DL.getIntPtrType((B.GetInsertBlock()->getContext()));
- Value *Calloc = M->getOrInsertFunction("calloc", Attrs, B.getInt8PtrTy(),
- PtrType, PtrType);
- CallInst *CI = B.CreateCall(Calloc, { Num, Size }, "calloc");
-
- if (const auto *F = dyn_cast<Function>(Calloc->stripPointerCasts()))
- CI->setCallingConv(F->getCallingConv());
-
- return CI;
-}
-
/// Fold memset[_chk](malloc(n), 0, n) --> calloc(1, n).
static Value *foldMallocMemset(CallInst *Memset, IRBuilder<> &B,
const TargetLibraryInfo &TLI) {
@@ -889,6 +868,13 @@
return CI->getArgOperand(0);
}
+Value *LibCallSimplifier::optimizeRealloc(CallInst *CI, IRBuilder<> &B) {
+ if (isa<ConstantPointerNull>(CI->getArgOperand(0)))
+ return emitMalloc(CI->getArgOperand(1), B, DL, TLI);
+
+ return nullptr;
+}
+
//===----------------------------------------------------------------------===//
// Math Library Optimizations
//===----------------------------------------------------------------------===//
@@ -2080,6 +2066,8 @@
return optimizeMemMove(CI, Builder);
case LibFunc_memset:
return optimizeMemSet(CI, Builder);
+ case LibFunc_realloc:
+ return optimizeRealloc(CI, Builder);
case LibFunc_wcslen:
return optimizeWcslen(CI, Builder);
default: