diff --git a/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h b/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
--- a/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
+++ b/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
@@ -85,7 +85,7 @@
 
   /// Emit a call to the strlen function to the builder, for the specified
   /// pointer. Ptr is required to be some pointer type, and the return value has
-  /// 'intptr_t' type.
+  /// 'size_t' type.
   Value *emitStrLen(Value *Ptr, IRBuilderBase &B, const DataLayout &DL,
                     const TargetLibraryInfo *TLI);
 
@@ -125,7 +125,7 @@
                      const TargetLibraryInfo *TLI);
 
   /// Emit a call to the __memcpy_chk function to the builder. This expects that
-  /// the Len and ObjSize have type 'intptr_t' and Dst/Src are pointers.
+  /// the Len and ObjSize have type 'size_t' and Dst/Src are pointers.
   Value *emitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,
                        IRBuilderBase &B, const DataLayout &DL,
                        const TargetLibraryInfo *TLI);
@@ -135,7 +135,7 @@
                      const DataLayout &DL, const TargetLibraryInfo *TLI);
 
   /// Emit a call to the memchr function. This assumes that Ptr is a pointer,
-  /// Val is an i32 value, and Len is an 'intptr_t' value.
+  /// Val is an 'int' value, and Len is an 'size_t' value.
   Value *emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilderBase &B,
                     const DataLayout &DL, const TargetLibraryInfo *TLI);
 
@@ -219,15 +219,15 @@
                                LibFunc FloatFn, LibFunc LongDoubleFn,
                                IRBuilderBase &B, const AttributeList &Attrs);
 
-  /// Emit a call to the putchar function. This assumes that Char is an integer.
+  /// Emit a call to the putchar function. This assumes that Char is an 'int'.
   Value *emitPutChar(Value *Char, IRBuilderBase &B,
                      const TargetLibraryInfo *TLI);
 
   /// Emit a call to the puts function. This assumes that Str is some pointer.
   Value *emitPutS(Value *Str, IRBuilderBase &B, const TargetLibraryInfo *TLI);
 
-  /// Emit a call to the fputc function. This assumes that Char is an i32, and
-  /// File is a pointer to FILE.
+  /// Emit a call to the fputc function. This assumes that Char can be casted to
+  /// int (currently assuming int is i32), and File is a pointer to FILE.
   Value *emitFPutC(Value *Char, Value *File, IRBuilderBase &B,
                    const TargetLibraryInfo *TLI);
 
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -1444,7 +1444,8 @@
 Value *llvm::emitStrLen(Value *Ptr, IRBuilderBase &B, const DataLayout &DL,
                         const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  return emitLibCall(LibFunc_strlen, DL.getIntPtrType(Context),
+  Type *SizeTTy = DL.getIntPtrType(Context);
+  return emitLibCall(LibFunc_strlen, SizeTTy,
                      B.getInt8PtrTy(), castToCStr(Ptr, B), B, TLI);
 }
 
@@ -1457,17 +1458,19 @@
 Value *llvm::emitStrChr(Value *Ptr, char C, IRBuilderBase &B,
                         const TargetLibraryInfo *TLI) {
   Type *I8Ptr = B.getInt8PtrTy();
-  Type *I32Ty = B.getInt32Ty();
-  return emitLibCall(LibFunc_strchr, I8Ptr, {I8Ptr, I32Ty},
-                     {castToCStr(Ptr, B), ConstantInt::get(I32Ty, C)}, B, TLI);
+  Type *IntTy = B.getInt32Ty();
+  return emitLibCall(LibFunc_strchr, I8Ptr, {I8Ptr, IntTy},
+                     {castToCStr(Ptr, B), ConstantInt::get(IntTy, C)}, B, TLI);
 }
 
 Value *llvm::emitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilderBase &B,
                          const DataLayout &DL, const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
+  Type *SizeTTy = DL.getIntPtrType(Context);
+  Type *IntTy = B.getInt32Ty();
   return emitLibCall(
-      LibFunc_strncmp, B.getInt32Ty(),
-      {B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context)},
+      LibFunc_strncmp, IntTy,
+      {B.getInt8PtrTy(), B.getInt8PtrTy(), SizeTTy},
       {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, B, TLI);
 }
 
@@ -1488,14 +1491,16 @@
 Value *llvm::emitStrNCpy(Value *Dst, Value *Src, Value *Len, IRBuilderBase &B,
                          const TargetLibraryInfo *TLI) {
   Type *I8Ptr = B.getInt8PtrTy();
-  return emitLibCall(LibFunc_strncpy, I8Ptr, {I8Ptr, I8Ptr, Len->getType()},
+  Type *SizeTTy = Len->getType();
+  return emitLibCall(LibFunc_strncpy, I8Ptr, {I8Ptr, I8Ptr, SizeTTy},
                      {castToCStr(Dst, B), castToCStr(Src, B), Len}, B, TLI);
 }
 
 Value *llvm::emitStpNCpy(Value *Dst, Value *Src, Value *Len, IRBuilderBase &B,
                          const TargetLibraryInfo *TLI) {
   Type *I8Ptr = B.getInt8PtrTy();
-  return emitLibCall(LibFunc_stpncpy, I8Ptr, {I8Ptr, I8Ptr, Len->getType()},
+  Type *SizeTTy = Len->getType();
+  return emitLibCall(LibFunc_stpncpy, I8Ptr, {I8Ptr, I8Ptr, SizeTTy},
                      {castToCStr(Dst, B), castToCStr(Src, B), Len}, B, TLI);
 }
 
@@ -1510,10 +1515,11 @@
   AS = AttributeList::get(M->getContext(), AttributeList::FunctionIndex,
                           Attribute::NoUnwind);
   LLVMContext &Context = B.GetInsertBlock()->getContext();
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *SizeTTy = DL.getIntPtrType(Context);
   FunctionCallee MemCpy = getOrInsertLibFunc(M, *TLI, LibFunc_memcpy_chk,
-      AttributeList::get(M->getContext(), AS), B.getInt8PtrTy(),
-      B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context),
-      DL.getIntPtrType(Context));
+      AttributeList::get(M->getContext(), AS), I8Ptr,
+      I8Ptr, I8Ptr, SizeTTy, SizeTTy);
   Dst = castToCStr(Dst, B);
   Src = castToCStr(Src, B);
   CallInst *CI = B.CreateCall(MemCpy, {Dst, Src, Len, ObjSize});
@@ -1526,73 +1532,92 @@
 Value *llvm::emitMemPCpy(Value *Dst, Value *Src, Value *Len, IRBuilderBase &B,
                          const DataLayout &DL, const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  return emitLibCall(
-      LibFunc_mempcpy, B.getInt8PtrTy(),
-      {B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context)},
-      {Dst, Src, Len}, B, TLI);
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *SizeTTy = DL.getIntPtrType(Context);
+  return emitLibCall(LibFunc_mempcpy, I8Ptr,
+                     {I8Ptr, I8Ptr, SizeTTy},
+                     {Dst, Src, Len}, B, TLI);
 }
 
 Value *llvm::emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilderBase &B,
                         const DataLayout &DL, const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  return emitLibCall(
-      LibFunc_memchr, B.getInt8PtrTy(),
-      {B.getInt8PtrTy(), B.getInt32Ty(), DL.getIntPtrType(Context)},
-      {castToCStr(Ptr, B), Val, Len}, B, TLI);
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = DL.getIntPtrType(Context);
+  return emitLibCall(LibFunc_memchr, I8Ptr,
+                     {I8Ptr, IntTy, SizeTTy},
+                     {castToCStr(Ptr, B), Val, Len}, B, TLI);
 }
 
 Value *llvm::emitMemRChr(Value *Ptr, Value *Val, Value *Len, IRBuilderBase &B,
                         const DataLayout &DL, const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  return emitLibCall(
-      LibFunc_memrchr, B.getInt8PtrTy(),
-      {B.getInt8PtrTy(), B.getInt32Ty(), DL.getIntPtrType(Context)},
-      {castToCStr(Ptr, B), Val, Len}, B, TLI);
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = DL.getIntPtrType(Context);
+  return emitLibCall(LibFunc_memrchr, I8Ptr,
+                     {I8Ptr, IntTy, SizeTTy},
+                     {castToCStr(Ptr, B), Val, Len}, B, TLI);
 }
 
 Value *llvm::emitMemCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilderBase &B,
                         const DataLayout &DL, const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = DL.getIntPtrType(Context);
   return emitLibCall(
-      LibFunc_memcmp, B.getInt32Ty(),
-      {B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context)},
+      LibFunc_memcmp, IntTy,
+      {I8Ptr, I8Ptr, SizeTTy},
       {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, B, TLI);
 }
 
 Value *llvm::emitBCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilderBase &B,
                       const DataLayout &DL, const TargetLibraryInfo *TLI) {
   LLVMContext &Context = B.GetInsertBlock()->getContext();
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = DL.getIntPtrType(Context);
   return emitLibCall(
-      LibFunc_bcmp, B.getInt32Ty(),
-      {B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context)},
+      LibFunc_bcmp, IntTy,
+      {I8Ptr, I8Ptr, SizeTTy},
       {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, B, TLI);
 }
 
 Value *llvm::emitMemCCpy(Value *Ptr1, Value *Ptr2, Value *Val, Value *Len,
                          IRBuilderBase &B, const TargetLibraryInfo *TLI) {
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = Len->getType();
   return emitLibCall(
-      LibFunc_memccpy, B.getInt8PtrTy(),
-      {B.getInt8PtrTy(), B.getInt8PtrTy(), B.getInt32Ty(), Len->getType()},
+      LibFunc_memccpy, I8Ptr,
+      {I8Ptr, I8Ptr, IntTy, SizeTTy},
       {Ptr1, Ptr2, Val, Len}, B, TLI);
 }
 
 Value *llvm::emitSNPrintf(Value *Dest, Value *Size, Value *Fmt,
                           ArrayRef<Value *> VariadicArgs, IRBuilderBase &B,
                           const TargetLibraryInfo *TLI) {
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = Size->getType();
   SmallVector<Value *, 8> Args{castToCStr(Dest, B), Size, castToCStr(Fmt, B)};
   llvm::append_range(Args, VariadicArgs);
-  return emitLibCall(LibFunc_snprintf, B.getInt32Ty(),
-                     {B.getInt8PtrTy(), Size->getType(), B.getInt8PtrTy()},
+  return emitLibCall(LibFunc_snprintf, IntTy,
+                     {I8Ptr, SizeTTy, I8Ptr},
                      Args, B, TLI, /*IsVaArgs=*/true);
 }
 
 Value *llvm::emitSPrintf(Value *Dest, Value *Fmt,
                          ArrayRef<Value *> VariadicArgs, IRBuilderBase &B,
                          const TargetLibraryInfo *TLI) {
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
   SmallVector<Value *, 8> Args{castToCStr(Dest, B), castToCStr(Fmt, B)};
   llvm::append_range(Args, VariadicArgs);
-  return emitLibCall(LibFunc_sprintf, B.getInt32Ty(),
-                     {B.getInt8PtrTy(), B.getInt8PtrTy()}, Args, B, TLI,
+  return emitLibCall(LibFunc_sprintf, IntTy,
+                     {I8Ptr, I8Ptr}, Args, B, TLI,
                      /*IsVaArgs=*/true);
 }
 
@@ -1605,37 +1630,48 @@
 
 Value *llvm::emitStrLCpy(Value *Dest, Value *Src, Value *Size, IRBuilderBase &B,
                          const TargetLibraryInfo *TLI) {
-  return emitLibCall(LibFunc_strlcpy, Size->getType(),
-                     {B.getInt8PtrTy(), B.getInt8PtrTy(), Size->getType()},
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *SizeTTy = Size->getType();
+  return emitLibCall(LibFunc_strlcpy, SizeTTy,
+                     {I8Ptr, I8Ptr, SizeTTy},
                      {castToCStr(Dest, B), castToCStr(Src, B), Size}, B, TLI);
 }
 
 Value *llvm::emitStrLCat(Value *Dest, Value *Src, Value *Size, IRBuilderBase &B,
                          const TargetLibraryInfo *TLI) {
-  return emitLibCall(LibFunc_strlcat, Size->getType(),
-                     {B.getInt8PtrTy(), B.getInt8PtrTy(), Size->getType()},
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *SizeTTy = Size->getType();
+  return emitLibCall(LibFunc_strlcat, SizeTTy,
+                     {I8Ptr, I8Ptr, SizeTTy},
                      {castToCStr(Dest, B), castToCStr(Src, B), Size}, B, TLI);
 }
 
 Value *llvm::emitStrNCat(Value *Dest, Value *Src, Value *Size, IRBuilderBase &B,
                          const TargetLibraryInfo *TLI) {
-  return emitLibCall(LibFunc_strncat, B.getInt8PtrTy(),
-                     {B.getInt8PtrTy(), B.getInt8PtrTy(), Size->getType()},
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *SizeTTy = Size->getType();
+  return emitLibCall(LibFunc_strncat, I8Ptr,
+                     {I8Ptr, I8Ptr, SizeTTy},
                      {castToCStr(Dest, B), castToCStr(Src, B), Size}, B, TLI);
 }
 
 Value *llvm::emitVSNPrintf(Value *Dest, Value *Size, Value *Fmt, Value *VAList,
                            IRBuilderBase &B, const TargetLibraryInfo *TLI) {
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  Type *SizeTTy = Size->getType();
   return emitLibCall(
-      LibFunc_vsnprintf, B.getInt32Ty(),
-      {B.getInt8PtrTy(), Size->getType(), B.getInt8PtrTy(), VAList->getType()},
+      LibFunc_vsnprintf, IntTy,
+      {I8Ptr, SizeTTy, I8Ptr, VAList->getType()},
       {castToCStr(Dest, B), Size, castToCStr(Fmt, B), VAList}, B, TLI);
 }
 
 Value *llvm::emitVSPrintf(Value *Dest, Value *Fmt, Value *VAList,
                           IRBuilderBase &B, const TargetLibraryInfo *TLI) {
-  return emitLibCall(LibFunc_vsprintf, B.getInt32Ty(),
-                     {B.getInt8PtrTy(), B.getInt8PtrTy(), VAList->getType()},
+  Type *I8Ptr = B.getInt8PtrTy();
+  Type *IntTy = B.getInt32Ty();
+  return emitLibCall(LibFunc_vsprintf, IntTy,
+                     {I8Ptr, I8Ptr, VAList->getType()},
                      {castToCStr(Dest, B), castToCStr(Fmt, B), VAList}, B, TLI);
 }
 
@@ -1764,9 +1800,10 @@
   if (!isLibFuncEmittable(M, TLI, LibFunc_putchar))
     return nullptr;
 
-  Type *Ty = Char->getType();
+  Type *IntTy = Char->getType();
   StringRef PutCharName = TLI->getName(LibFunc_putchar);
-  FunctionCallee PutChar = getOrInsertLibFunc(M, *TLI, LibFunc_putchar, Ty, Ty);
+  FunctionCallee PutChar = getOrInsertLibFunc(M, *TLI, LibFunc_putchar,
+                                              IntTy, IntTy);
   inferNonMandatoryLibFuncAttrs(M, PutCharName, *TLI);
   CallInst *CI = B.CreateCall(PutChar, Char, PutCharName);
 
@@ -1782,8 +1819,9 @@
   if (!isLibFuncEmittable(M, TLI, LibFunc_puts))
     return nullptr;
 
+  Type *IntTy = B.getInt32Ty();
   StringRef PutsName = TLI->getName(LibFunc_puts);
-  FunctionCallee PutS = getOrInsertLibFunc(M, *TLI, LibFunc_puts, B.getInt32Ty(),
+  FunctionCallee PutS = getOrInsertLibFunc(M, *TLI, LibFunc_puts, IntTy,
                                            B.getInt8PtrTy());
   inferNonMandatoryLibFuncAttrs(M, PutsName, *TLI);
   CallInst *CI = B.CreateCall(PutS, castToCStr(Str, B), PutsName);
@@ -1799,12 +1837,13 @@
   if (!isLibFuncEmittable(M, TLI, LibFunc_fputc))
     return nullptr;
 
+  Type *IntTy = B.getInt32Ty();
   StringRef FPutcName = TLI->getName(LibFunc_fputc);
-  FunctionCallee F = getOrInsertLibFunc(M, *TLI, LibFunc_fputc, B.getInt32Ty(),
-                                        B.getInt32Ty(), File->getType());
+  FunctionCallee F = getOrInsertLibFunc(M, *TLI, LibFunc_fputc, IntTy,
+                                        IntTy, File->getType());
   if (File->getType()->isPointerTy())
     inferNonMandatoryLibFuncAttrs(M, FPutcName, *TLI);
-  Char = B.CreateIntCast(Char, B.getInt32Ty(), /*isSigned*/true,
+  Char = B.CreateIntCast(Char, IntTy, /*isSigned*/true,
                          "chari");
   CallInst *CI = B.CreateCall(F, {Char, File}, FPutcName);
 
@@ -1820,8 +1859,9 @@
   if (!isLibFuncEmittable(M, TLI, LibFunc_fputs))
     return nullptr;
 
+  Type *IntTy = B.getInt32Ty();
   StringRef FPutsName = TLI->getName(LibFunc_fputs);
-  FunctionCallee F = getOrInsertLibFunc(M, *TLI, LibFunc_fputs, B.getInt32Ty(),
+  FunctionCallee F = getOrInsertLibFunc(M, *TLI, LibFunc_fputs, IntTy,
                                         B.getInt8PtrTy(), File->getType());
   if (File->getType()->isPointerTy())
     inferNonMandatoryLibFuncAttrs(M, FPutsName, *TLI);
@@ -1840,10 +1880,11 @@
     return nullptr;
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
+  Type *SizeTTy = DL.getIntPtrType(Context);
   StringRef FWriteName = TLI->getName(LibFunc_fwrite);
   FunctionCallee F = getOrInsertLibFunc(M, *TLI, LibFunc_fwrite,
-       DL.getIntPtrType(Context), B.getInt8PtrTy(), DL.getIntPtrType(Context),
-       DL.getIntPtrType(Context), File->getType());
+                                        SizeTTy, B.getInt8PtrTy(), SizeTTy,
+                                        SizeTTy, File->getType());
 
   if (File->getType()->isPointerTy())
     inferNonMandatoryLibFuncAttrs(M, FWriteName, *TLI);
@@ -1865,8 +1906,9 @@
 
   StringRef MallocName = TLI->getName(LibFunc_malloc);
   LLVMContext &Context = B.GetInsertBlock()->getContext();
+  Type *SizeTTy = DL.getIntPtrType(Context);
   FunctionCallee Malloc = getOrInsertLibFunc(M, *TLI, LibFunc_malloc,
-                                 B.getInt8PtrTy(), DL.getIntPtrType(Context));
+                                             B.getInt8PtrTy(), SizeTTy);
   inferNonMandatoryLibFuncAttrs(M, MallocName, *TLI);
   CallInst *CI = B.CreateCall(Malloc, Num, MallocName);
 
@@ -1884,10 +1926,11 @@
     return nullptr;
 
   StringRef CallocName = TLI.getName(LibFunc_calloc);
+  LLVMContext &Context = B.GetInsertBlock()->getContext();
   const DataLayout &DL = M->getDataLayout();
-  IntegerType *PtrType = DL.getIntPtrType((B.GetInsertBlock()->getContext()));
+  Type *SizeTTy = DL.getIntPtrType(Context);
   FunctionCallee Calloc = getOrInsertLibFunc(M, TLI, LibFunc_calloc,
-                                             B.getInt8PtrTy(), PtrType, PtrType);
+                                             B.getInt8PtrTy(), SizeTTy, SizeTTy);
   inferNonMandatoryLibFuncAttrs(M, CallocName, TLI);
   CallInst *CI = B.CreateCall(Calloc, {Num, Size}, CallocName);