[TLI] Unify LibFunc attribute inference. NFCI.

[ab]

Summary

Now the pass is just a tiny wrapper around the util. This lets us reuse the logic elsewhere (done here for BuildLibCalls) instead of duplicating it.

I put it in BuildLibCalls.h. I think the next step is to have something like getOrInsertLibFunc that also sets the attributes.
I tried having this in TLI itself, but that doesn't feel right for an analysis. I also tried having the analysis return an AttributeSet that users would then apply; I think that's still a little awkward though. Thoughts?

[mehdi_amini]

Skimmed through, you remove a lot of lines, I like it ;)

LGTM.

lib/Transforms/Utils/BuildLibCalls.cpp

742 ↗

(On Diff #54808)

Looks like we could refactor all of these under something like TLI::get(M, "strchr")?

[ab]

Thanks for the reviews!

lib/Transforms/Utils/BuildLibCalls.cpp

742 ↗

(On Diff #54808)

Yup, I'm doing that next, separately.

llvm/trunk/include/llvm/Transforms/Utils/BuildLibCalls.h

 
 #include "llvm/IR/IRBuilder.h"
 
 namespace llvm {
   class Value;
   class DataLayout;
   class TargetLibraryInfo;
 
+  /// Analyze the name and prototype of the given function and set any
+  /// applicable attributes.
+  /// If the library function is unavailable, this doesn't modify it.
+  ///
+  /// Returns true if any attributes were set and false otherwise.
+  bool inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI);
+
   /// Return V if it is an i8*, otherwise cast it to i8*.
   Value *castToCStr(Value *V, IRBuilder<> &B);
 
   /// 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.
   Value *emitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout &DL,
                     const TargetLibraryInfo *TLI);

llvm/trunk/lib/Transforms/IPO/InferFunctionAttrs.cpp

 //===- InferFunctionAttrs.cpp - Infer implicit function attributes --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/IPO/InferFunctionAttrs.h"
-#include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/BuildLibCalls.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "inferattrs"
 
-STATISTIC(NumReadNone, "Number of functions inferred as readnone");
-STATISTIC(NumReadOnly, "Number of functions inferred as readonly");
-STATISTIC(NumArgMemOnly, "Number of functions inferred as argmemonly");
-STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
-STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
-STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
-STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
-STATISTIC(NumNonNull, "Number of function returns inferred as nonnull returns");
-
-static bool setDoesNotAccessMemory(Function &F) {
-  if (F.doesNotAccessMemory())
-    return false;
-  F.setDoesNotAccessMemory();
-  ++NumReadNone;
-  return true;
-}
-
-static bool setOnlyReadsMemory(Function &F) {
-  if (F.onlyReadsMemory())
-    return false;
-  F.setOnlyReadsMemory();
-  ++NumReadOnly;
-  return true;
-}
-
-static bool setOnlyAccessesArgMemory(Function &F) {
-  if (F.onlyAccessesArgMemory())
-    return false;
-  F.setOnlyAccessesArgMemory ();
-  ++NumArgMemOnly;
-  return true;
-}
-
-
-static bool setDoesNotThrow(Function &F) {
-  if (F.doesNotThrow())
-    return false;
-  F.setDoesNotThrow();
-  ++NumNoUnwind;
-  return true;
-}
-
-static bool setDoesNotCapture(Function &F, unsigned n) {
-  if (F.doesNotCapture(n))
-    return false;
-  F.setDoesNotCapture(n);
-  ++NumNoCapture;
-  return true;
-}
-
-static bool setOnlyReadsMemory(Function &F, unsigned n) {
-  if (F.onlyReadsMemory(n))
-    return false;
-  F.setOnlyReadsMemory(n);
-  ++NumReadOnlyArg;
-  return true;
-}
-
-static bool setDoesNotAlias(Function &F, unsigned n) {
-  if (F.doesNotAlias(n))
-    return false;
-  F.setDoesNotAlias(n);
-  ++NumNoAlias;
-  return true;
-}
-
-static bool setNonNull(Function &F, unsigned n) {
-  assert((n != AttributeSet::ReturnIndex ||
-          F.getReturnType()->isPointerTy()) &&
-         "nonnull applies only to pointers");
-  if (F.getAttributes().hasAttribute(n, Attribute::NonNull))
-    return false;
-  F.addAttribute(n, Attribute::NonNull);
-  ++NumNonNull;
-  return true;
-}
-
-/// Analyze the name and prototype of the given function and set any applicable
-/// attributes.
-///
-/// Returns true if any attributes were set and false otherwise.
-static bool inferPrototypeAttributes(Function &F,
-                                     const TargetLibraryInfo &TLI) {
-  if (F.hasFnAttribute(Attribute::OptimizeNone))
-    return false;
-
-  LibFunc::Func TheLibFunc;
-  if (!(TLI.getLibFunc(F, TheLibFunc) && TLI.has(TheLibFunc)))
-    return false;
-
-  bool Changed = false;
-  switch (TheLibFunc) {
-  case LibFunc::strlen:
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::strchr:
-  case LibFunc::strrchr:
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotThrow(F);
-    return Changed;
-  case LibFunc::strtol:
-  case LibFunc::strtod:
-  case LibFunc::strtof:
-  case LibFunc::strtoul:
-  case LibFunc::strtoll:
-  case LibFunc::strtold:
-  case LibFunc::strtoull:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::strcpy:
-  case LibFunc::stpcpy:
-  case LibFunc::strcat:
-  case LibFunc::strncat:
-  case LibFunc::strncpy:
-  case LibFunc::stpncpy:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::strxfrm:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::strcmp:      // 0,1
-  case LibFunc::strspn:      // 0,1
-  case LibFunc::strncmp:     // 0,1
-  case LibFunc::strcspn:     // 0,1
-  case LibFunc::strcoll:     // 0,1
-  case LibFunc::strcasecmp:  // 0,1
-  case LibFunc::strncasecmp: //
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::strstr:
-  case LibFunc::strpbrk:
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::strtok:
-  case LibFunc::strtok_r:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::scanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::setbuf:
-  case LibFunc::setvbuf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::strdup:
-  case LibFunc::strndup:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::stat:
-  case LibFunc::statvfs:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::sscanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::sprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::snprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 3);
-    Changed |= setOnlyReadsMemory(F, 3);
-    return Changed;
-  case LibFunc::setitimer:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setDoesNotCapture(F, 3);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::system:
-    // May throw; "system" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::malloc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    return Changed;
-  case LibFunc::memcmp:
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::memchr:
-  case LibFunc::memrchr:
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotThrow(F);
-    return Changed;
-  case LibFunc::modf:
-  case LibFunc::modff:
-  case LibFunc::modfl:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::memcpy:
-  case LibFunc::memccpy:
-  case LibFunc::memmove:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::memalign:
-    Changed |= setDoesNotAlias(F, 0);
-    return Changed;
-  case LibFunc::mkdir:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::mktime:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::realloc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::read:
-    // May throw; "read" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::rewind:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::rmdir:
-  case LibFunc::remove:
-  case LibFunc::realpath:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::rename:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::readlink:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::write:
-    // May throw; "write" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::bcopy:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::bcmp:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::bzero:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::calloc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    return Changed;
-  case LibFunc::chmod:
-  case LibFunc::chown:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::ctermid:
-  case LibFunc::clearerr:
-  case LibFunc::closedir:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::atoi:
-  case LibFunc::atol:
-  case LibFunc::atof:
-  case LibFunc::atoll:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::access:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::fopen:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::fdopen:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::feof:
-  case LibFunc::free:
-  case LibFunc::fseek:
-  case LibFunc::ftell:
-  case LibFunc::fgetc:
-  case LibFunc::fseeko:
-  case LibFunc::ftello:
-  case LibFunc::fileno:
-  case LibFunc::fflush:
-  case LibFunc::fclose:
-  case LibFunc::fsetpos:
-  case LibFunc::flockfile:
-  case LibFunc::funlockfile:
-  case LibFunc::ftrylockfile:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::ferror:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F);
-    return Changed;
-  case LibFunc::fputc:
-  case LibFunc::fstat:
-  case LibFunc::frexp:
-  case LibFunc::frexpf:
-  case LibFunc::frexpl:
-  case LibFunc::fstatvfs:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::fgets:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 3);
-    return Changed;
-  case LibFunc::fread:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 4);
-    return Changed;
-  case LibFunc::fwrite:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 4);
-    return Changed;
-  case LibFunc::fputs:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::fscanf:
-  case LibFunc::fprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::fgetpos:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::getc:
-  case LibFunc::getlogin_r:
-  case LibFunc::getc_unlocked:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::getenv:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setOnlyReadsMemory(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::gets:
-  case LibFunc::getchar:
-    Changed |= setDoesNotThrow(F);
-    return Changed;
-  case LibFunc::getitimer:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::getpwnam:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::ungetc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::uname:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::unlink:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::unsetenv:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::utime:
-  case LibFunc::utimes:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::putc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::puts:
-  case LibFunc::printf:
-  case LibFunc::perror:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::pread:
-    // May throw; "pread" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::pwrite:
-    // May throw; "pwrite" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::putchar:
-    Changed |= setDoesNotThrow(F);
-    return Changed;
-  case LibFunc::popen:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::pclose:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::vscanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::vsscanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::vfscanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::valloc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    return Changed;
-  case LibFunc::vprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::vfprintf:
-  case LibFunc::vsprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::vsnprintf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 3);
-    Changed |= setOnlyReadsMemory(F, 3);
-    return Changed;
-  case LibFunc::open:
-    // May throw; "open" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::opendir:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::tmpfile:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    return Changed;
-  case LibFunc::times:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::htonl:
-  case LibFunc::htons:
-  case LibFunc::ntohl:
-  case LibFunc::ntohs:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAccessMemory(F);
-    return Changed;
-  case LibFunc::lstat:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::lchown:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::qsort:
-    // May throw; places call through function pointer.
-    Changed |= setDoesNotCapture(F, 4);
-    return Changed;
-  case LibFunc::dunder_strdup:
-  case LibFunc::dunder_strndup:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::dunder_strtok_r:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::under_IO_getc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::under_IO_putc:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::dunder_isoc99_scanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::stat64:
-  case LibFunc::lstat64:
-  case LibFunc::statvfs64:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::dunder_isoc99_sscanf:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::fopen64:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    Changed |= setOnlyReadsMemory(F, 1);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  case LibFunc::fseeko64:
-  case LibFunc::ftello64:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    return Changed;
-  case LibFunc::tmpfile64:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotAlias(F, 0);
-    return Changed;
-  case LibFunc::fstat64:
-  case LibFunc::fstatvfs64:
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::open64:
-    // May throw; "open" is a valid pthread cancellation point.
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
-  case LibFunc::gettimeofday:
-    // Currently some platforms have the restrict keyword on the arguments to
-    // gettimeofday. To be conservative, do not add noalias to gettimeofday's
-    // arguments.
-    Changed |= setDoesNotThrow(F);
-    Changed |= setDoesNotCapture(F, 1);
-    Changed |= setDoesNotCapture(F, 2);
-    return Changed;
-  case LibFunc::Znwj: // new(unsigned int)
-  case LibFunc::Znwm: // new(unsigned long)
-  case LibFunc::Znaj: // new[](unsigned int)
-  case LibFunc::Znam: // new[](unsigned long)
-  case LibFunc::msvc_new_int: // new(unsigned int)
-  case LibFunc::msvc_new_longlong: // new(unsigned long long)
-  case LibFunc::msvc_new_array_int: // new[](unsigned int)
-  case LibFunc::msvc_new_array_longlong: // new[](unsigned long long)
-    // Operator new always returns a nonnull noalias pointer
-    Changed |= setNonNull(F, AttributeSet::ReturnIndex);
-    Changed |= setDoesNotAlias(F, AttributeSet::ReturnIndex);
-    return Changed;
-  //TODO: add LibFunc entries for:
-  //case LibFunc::memset_pattern4:
-  //case LibFunc::memset_pattern8:
-  case LibFunc::memset_pattern16:
-    Changed |= setOnlyAccessesArgMemory(F);
-    Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
-  // int __nvvm_reflect(const char *)
-  case LibFunc::nvvm_reflect:
-    Changed |= setDoesNotAccessMemory(F);
-    Changed |= setDoesNotThrow(F);
-    return Changed;
-
-  default:
-    // FIXME: It'd be really nice to cover all the library functions we're
-    // aware of here.
-    return false;
-  }
-}
-
 static bool inferAllPrototypeAttributes(Module &M,
                                         const TargetLibraryInfo &TLI) {
   bool Changed = false;
 
   for (Function &F : M.functions())
-    // We only infer things using the prototype if the definition isn't around
-    // to analyze directly.
-    if (F.isDeclaration())
-      Changed |= inferPrototypeAttributes(F, TLI);
+    // We only infer things using the prototype and the name; we don't need
+    // definitions.
+    if (F.isDeclaration() && !F.hasFnAttribute((Attribute::OptimizeNone)))
+      Changed |= inferLibFuncAttributes(F, TLI);
 
   return Changed;
 }
 
 PreservedAnalyses InferFunctionAttrsPass::run(Module &M,
                                               AnalysisManager<Module> &AM) {
   auto &TLI = AM.getResult<TargetLibraryAnalysis>(M);
 

llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp

 //===- BuildLibCalls.cpp - Utility builder for libcalls -------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements some functions that will create standard C libcalls.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/BuildLibCalls.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Type.h"
 
 using namespace llvm;
 
+#define DEBUG_TYPE "build-libcalls"
+
+//- Infer Attributes ---------------------------------------------------------//
+
+STATISTIC(NumReadNone, "Number of functions inferred as readnone");
+STATISTIC(NumReadOnly, "Number of functions inferred as readonly");
+STATISTIC(NumArgMemOnly, "Number of functions inferred as argmemonly");
+STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
+STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
+STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
+STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
+STATISTIC(NumNonNull, "Number of function returns inferred as nonnull returns");
+
+static bool setDoesNotAccessMemory(Function &F) {
+  if (F.doesNotAccessMemory())
+    return false;
+  F.setDoesNotAccessMemory();
+  ++NumReadNone;
+  return true;
+}
+
+static bool setOnlyReadsMemory(Function &F) {
+  if (F.onlyReadsMemory())
+    return false;
+  F.setOnlyReadsMemory();
+  ++NumReadOnly;
+  return true;
+}
+
+static bool setOnlyAccessesArgMemory(Function &F) {
+  if (F.onlyAccessesArgMemory())
+    return false;
+  F.setOnlyAccessesArgMemory ();
+  ++NumArgMemOnly;
+  return true;
+}
+
+static bool setDoesNotThrow(Function &F) {
+  if (F.doesNotThrow())
+    return false;
+  F.setDoesNotThrow();
+  ++NumNoUnwind;
+  return true;
+}
+
+static bool setDoesNotCapture(Function &F, unsigned n) {
+  if (F.doesNotCapture(n))
+    return false;
+  F.setDoesNotCapture(n);
+  ++NumNoCapture;
+  return true;
+}
+
+static bool setOnlyReadsMemory(Function &F, unsigned n) {
+  if (F.onlyReadsMemory(n))
+    return false;
+  F.setOnlyReadsMemory(n);
+  ++NumReadOnlyArg;
+  return true;
+}
+
+static bool setDoesNotAlias(Function &F, unsigned n) {
+  if (F.doesNotAlias(n))
+    return false;
+  F.setDoesNotAlias(n);
+  ++NumNoAlias;
+  return true;
+}
+
+static bool setNonNull(Function &F, unsigned n) {
+  assert((n != AttributeSet::ReturnIndex ||
+          F.getReturnType()->isPointerTy()) &&
+         "nonnull applies only to pointers");
+  if (F.getAttributes().hasAttribute(n, Attribute::NonNull))
+    return false;
+  F.addAttribute(n, Attribute::NonNull);
+  ++NumNonNull;
+  return true;
+}
+
+bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
+  LibFunc::Func TheLibFunc;
+  if (!(TLI.getLibFunc(F, TheLibFunc) && TLI.has(TheLibFunc)))
+    return false;
+
+  bool Changed = false;
+  switch (TheLibFunc) {
+  case LibFunc::strlen:
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::strchr:
+  case LibFunc::strrchr:
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+  case LibFunc::strtol:
+  case LibFunc::strtod:
+  case LibFunc::strtof:
+  case LibFunc::strtoul:
+  case LibFunc::strtoll:
+  case LibFunc::strtold:
+  case LibFunc::strtoull:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::strcpy:
+  case LibFunc::stpcpy:
+  case LibFunc::strcat:
+  case LibFunc::strncat:
+  case LibFunc::strncpy:
+  case LibFunc::stpncpy:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::strxfrm:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::strcmp:      // 0,1
+  case LibFunc::strspn:      // 0,1
+  case LibFunc::strncmp:     // 0,1
+  case LibFunc::strcspn:     // 0,1
+  case LibFunc::strcoll:     // 0,1
+  case LibFunc::strcasecmp:  // 0,1
+  case LibFunc::strncasecmp: //
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::strstr:
+  case LibFunc::strpbrk:
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::strtok:
+  case LibFunc::strtok_r:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::scanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::setbuf:
+  case LibFunc::setvbuf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::strdup:
+  case LibFunc::strndup:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::stat:
+  case LibFunc::statvfs:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::sscanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::sprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::snprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 3);
+    Changed |= setOnlyReadsMemory(F, 3);
+    return Changed;
+  case LibFunc::setitimer:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setDoesNotCapture(F, 3);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::system:
+    // May throw; "system" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::malloc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    return Changed;
+  case LibFunc::memcmp:
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::memchr:
+  case LibFunc::memrchr:
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+  case LibFunc::modf:
+  case LibFunc::modff:
+  case LibFunc::modfl:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::memcpy:
+  case LibFunc::memccpy:
+  case LibFunc::memmove:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::memcpy_chk:
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+  case LibFunc::memalign:
+    Changed |= setDoesNotAlias(F, 0);
+    return Changed;
+  case LibFunc::mkdir:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::mktime:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::realloc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::read:
+    // May throw; "read" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::rewind:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::rmdir:
+  case LibFunc::remove:
+  case LibFunc::realpath:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::rename:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::readlink:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::write:
+    // May throw; "write" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::bcopy:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::bcmp:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::bzero:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::calloc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    return Changed;
+  case LibFunc::chmod:
+  case LibFunc::chown:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::ctermid:
+  case LibFunc::clearerr:
+  case LibFunc::closedir:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::atoi:
+  case LibFunc::atol:
+  case LibFunc::atof:
+  case LibFunc::atoll:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::access:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::fopen:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::fdopen:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::feof:
+  case LibFunc::free:
+  case LibFunc::fseek:
+  case LibFunc::ftell:
+  case LibFunc::fgetc:
+  case LibFunc::fseeko:
+  case LibFunc::ftello:
+  case LibFunc::fileno:
+  case LibFunc::fflush:
+  case LibFunc::fclose:
+  case LibFunc::fsetpos:
+  case LibFunc::flockfile:
+  case LibFunc::funlockfile:
+  case LibFunc::ftrylockfile:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::ferror:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F);
+    return Changed;
+  case LibFunc::fputc:
+  case LibFunc::fstat:
+  case LibFunc::frexp:
+  case LibFunc::frexpf:
+  case LibFunc::frexpl:
+  case LibFunc::fstatvfs:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::fgets:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 3);
+    return Changed;
+  case LibFunc::fread:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 4);
+    return Changed;
+  case LibFunc::fwrite:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 4);
+    // FIXME: readonly #1?
+    return Changed;
+  case LibFunc::fputs:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::fscanf:
+  case LibFunc::fprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::fgetpos:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::getc:
+  case LibFunc::getlogin_r:
+  case LibFunc::getc_unlocked:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::getenv:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setOnlyReadsMemory(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::gets:
+  case LibFunc::getchar:
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+  case LibFunc::getitimer:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::getpwnam:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::ungetc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::uname:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::unlink:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::unsetenv:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::utime:
+  case LibFunc::utimes:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::putc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::puts:
+  case LibFunc::printf:
+  case LibFunc::perror:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::pread:
+    // May throw; "pread" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::pwrite:
+    // May throw; "pwrite" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::putchar:
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+  case LibFunc::popen:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::pclose:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::vscanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::vsscanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::vfscanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::valloc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    return Changed;
+  case LibFunc::vprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::vfprintf:
+  case LibFunc::vsprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::vsnprintf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 3);
+    Changed |= setOnlyReadsMemory(F, 3);
+    return Changed;
+  case LibFunc::open:
+    // May throw; "open" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::opendir:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::tmpfile:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    return Changed;
+  case LibFunc::times:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::htonl:
+  case LibFunc::htons:
+  case LibFunc::ntohl:
+  case LibFunc::ntohs:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAccessMemory(F);
+    return Changed;
+  case LibFunc::lstat:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::lchown:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::qsort:
+    // May throw; places call through function pointer.
+    Changed |= setDoesNotCapture(F, 4);
+    return Changed;
+  case LibFunc::dunder_strdup:
+  case LibFunc::dunder_strndup:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::dunder_strtok_r:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::under_IO_getc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::under_IO_putc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::dunder_isoc99_scanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::stat64:
+  case LibFunc::lstat64:
+  case LibFunc::statvfs64:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::dunder_isoc99_sscanf:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::fopen64:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    Changed |= setOnlyReadsMemory(F, 1);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  case LibFunc::fseeko64:
+  case LibFunc::ftello64:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    return Changed;
+  case LibFunc::tmpfile64:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotAlias(F, 0);
+    return Changed;
+  case LibFunc::fstat64:
+  case LibFunc::fstatvfs64:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::open64:
+    // May throw; "open" is a valid pthread cancellation point.
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setOnlyReadsMemory(F, 1);
+    return Changed;
+  case LibFunc::gettimeofday:
+    // Currently some platforms have the restrict keyword on the arguments to
+    // gettimeofday. To be conservative, do not add noalias to gettimeofday's
+    // arguments.
+    Changed |= setDoesNotThrow(F);
+    Changed |= setDoesNotCapture(F, 1);
+    Changed |= setDoesNotCapture(F, 2);
+    return Changed;
+  case LibFunc::Znwj: // new(unsigned int)
+  case LibFunc::Znwm: // new(unsigned long)
+  case LibFunc::Znaj: // new[](unsigned int)
+  case LibFunc::Znam: // new[](unsigned long)
+  case LibFunc::msvc_new_int: // new(unsigned int)
+  case LibFunc::msvc_new_longlong: // new(unsigned long long)
+  case LibFunc::msvc_new_array_int: // new[](unsigned int)
+  case LibFunc::msvc_new_array_longlong: // new[](unsigned long long)
+    // Operator new always returns a nonnull noalias pointer
+    Changed |= setNonNull(F, AttributeSet::ReturnIndex);
+    Changed |= setDoesNotAlias(F, AttributeSet::ReturnIndex);
+    return Changed;
+  //TODO: add LibFunc entries for:
+  //case LibFunc::memset_pattern4:
+  //case LibFunc::memset_pattern8:
+  case LibFunc::memset_pattern16:
+    Changed |= setOnlyAccessesArgMemory(F);
+    Changed |= setOnlyReadsMemory(F, 2);
+    return Changed;
+  // int __nvvm_reflect(const char *)
+  case LibFunc::nvvm_reflect:
+    Changed |= setDoesNotAccessMemory(F);
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+
+  default:
+    // FIXME: It'd be really nice to cover all the library functions we're
+    // aware of here.
+    return false;
+  }
+}
+
+//- Emit LibCalls ------------------------------------------------------------//
+
 Value *llvm::castToCStr(Value *V, IRBuilder<> &B) {
   unsigned AS = V->getType()->getPointerAddressSpace();
   return B.CreateBitCast(V, B.getInt8PtrTy(AS), "cstr");
 }
 
 Value *llvm::emitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout &DL,
                         const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::strlen))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[2];
-  AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
-  Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
-
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Constant *StrLen = M->getOrInsertFunction(
-      "strlen", AttributeSet::get(M->getContext(), AS),
-      DL.getIntPtrType(Context), B.getInt8PtrTy(), nullptr);
+  Constant *StrLen = M->getOrInsertFunction("strlen", DL.getIntPtrType(Context),
+                                            B.getInt8PtrTy(), nullptr);
+  inferLibFuncAttributes(*M->getFunction("strlen"), *TLI);
   CallInst *CI = B.CreateCall(StrLen, castToCStr(Ptr, B), "strlen");
   if (const Function *F = dyn_cast<Function>(StrLen->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
 
   return CI;
 }
 
 Value *llvm::emitStrChr(Value *Ptr, char C, IRBuilder<> &B,
                         const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::strchr))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AttributeSet AS =
-    AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
-
   Type *I8Ptr = B.getInt8PtrTy();
   Type *I32Ty = B.getInt32Ty();
-  Constant *StrChr = M->getOrInsertFunction("strchr",
-                                            AttributeSet::get(M->getContext(),
-                                                             AS),
-                                            I8Ptr, I8Ptr, I32Ty, nullptr);
+  Constant *StrChr =
+      M->getOrInsertFunction("strchr", I8Ptr, I8Ptr, I32Ty, nullptr);
+  inferLibFuncAttributes(*M->getFunction("strchr"), *TLI);
   CallInst *CI = B.CreateCall(
       StrChr, {castToCStr(Ptr, B), ConstantInt::get(I32Ty, C)}, "strchr");
   if (const Function *F = dyn_cast<Function>(StrChr->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
   return CI;
 }
 
 Value *llvm::emitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilder<> &B,
                          const DataLayout &DL, const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::strncmp))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[3];
-  AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
-  Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
-
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Value *StrNCmp = M->getOrInsertFunction(
-      "strncmp", AttributeSet::get(M->getContext(), AS), B.getInt32Ty(),
-      B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context), nullptr);
+  Value *StrNCmp = M->getOrInsertFunction("strncmp", B.getInt32Ty(),
+                                          B.getInt8PtrTy(), B.getInt8PtrTy(),
+                                          DL.getIntPtrType(Context), nullptr);
+  inferLibFuncAttributes(*M->getFunction("strncmp"), *TLI);
   CallInst *CI = B.CreateCall(
       StrNCmp, {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, "strncmp");
 
   if (const Function *F = dyn_cast<Function>(StrNCmp->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
 
   return CI;
 }
 
 Value *llvm::emitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
                         const TargetLibraryInfo *TLI, StringRef Name) {
   if (!TLI->has(LibFunc::strcpy))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[2];
-  AS[0] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::NoUnwind);
   Type *I8Ptr = B.getInt8PtrTy();
-  Value *StrCpy = M->getOrInsertFunction(Name,
-                                         AttributeSet::get(M->getContext(), AS),
-                                         I8Ptr, I8Ptr, I8Ptr, nullptr);
+  Value *StrCpy = M->getOrInsertFunction(Name, I8Ptr, I8Ptr, I8Ptr, nullptr);
+  inferLibFuncAttributes(*M->getFunction(Name), *TLI);
   CallInst *CI =
       B.CreateCall(StrCpy, {castToCStr(Dst, B), castToCStr(Src, B)}, Name);
   if (const Function *F = dyn_cast<Function>(StrCpy->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
   return CI;
 }
 
 Value *llvm::emitStrNCpy(Value *Dst, Value *Src, Value *Len, IRBuilder<> &B,
                          const TargetLibraryInfo *TLI, StringRef Name) {
   if (!TLI->has(LibFunc::strncpy))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[2];
-  AS[0] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::NoUnwind);
   Type *I8Ptr = B.getInt8PtrTy();
-  Value *StrNCpy = M->getOrInsertFunction(Name,
-                                          AttributeSet::get(M->getContext(),
-                                                            AS),
-                                          I8Ptr, I8Ptr, I8Ptr,
+  Value *StrNCpy = M->getOrInsertFunction(Name, I8Ptr, I8Ptr, I8Ptr,
                                           Len->getType(), nullptr);
+  inferLibFuncAttributes(*M->getFunction(Name), *TLI);
   CallInst *CI = B.CreateCall(
       StrNCpy, {castToCStr(Dst, B), castToCStr(Src, B), Len}, "strncpy");
   if (const Function *F = dyn_cast<Function>(StrNCpy->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
   return CI;
 }
 
 Value *llvm::emitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,

 }
 
 Value *llvm::emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilder<> &B,
                         const DataLayout &DL, const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::memchr))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS;
-  Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Value *MemChr = M->getOrInsertFunction(
-      "memchr", AttributeSet::get(M->getContext(), AS), B.getInt8PtrTy(),
-      B.getInt8PtrTy(), B.getInt32Ty(), DL.getIntPtrType(Context), nullptr);
+  Value *MemChr = M->getOrInsertFunction("memchr", B.getInt8PtrTy(),
+                                         B.getInt8PtrTy(), B.getInt32Ty(),
+                                         DL.getIntPtrType(Context), nullptr);
+  inferLibFuncAttributes(*M->getFunction("memchr"), *TLI);
   CallInst *CI = B.CreateCall(MemChr, {castToCStr(Ptr, B), Val, Len}, "memchr");
 
   if (const Function *F = dyn_cast<Function>(MemChr->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
 
   return CI;
 }
 
 Value *llvm::emitMemCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilder<> &B,
                         const DataLayout &DL, const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::memcmp))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[3];
-  AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
-  Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
-
   LLVMContext &Context = B.GetInsertBlock()->getContext();
-  Value *MemCmp = M->getOrInsertFunction(
-      "memcmp", AttributeSet::get(M->getContext(), AS), B.getInt32Ty(),
-      B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context), nullptr);
+  Value *MemCmp = M->getOrInsertFunction("memcmp", B.getInt32Ty(),
+                                         B.getInt8PtrTy(), B.getInt8PtrTy(),
+                                         DL.getIntPtrType(Context), nullptr);
+  inferLibFuncAttributes(*M->getFunction("memcmp"), *TLI);
   CallInst *CI = B.CreateCall(
       MemCmp, {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, "memcmp");
 
   if (const Function *F = dyn_cast<Function>(MemCmp->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
 
   return CI;
 }

 }
 
 Value *llvm::emitPutS(Value *Str, IRBuilder<> &B,
                       const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::puts))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[2];
-  AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::NoUnwind);
-
-  Value *PutS = M->getOrInsertFunction("puts",
-                                       AttributeSet::get(M->getContext(), AS),
-                                       B.getInt32Ty(),
-                                       B.getInt8PtrTy(),
-                                       nullptr);
+  Value *PutS =
+      M->getOrInsertFunction("puts", B.getInt32Ty(), B.getInt8PtrTy(), nullptr);
+  inferLibFuncAttributes(*M->getFunction("puts"), *TLI);
   CallInst *CI = B.CreateCall(PutS, castToCStr(Str, B), "puts");
   if (const Function *F = dyn_cast<Function>(PutS->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
   return CI;
 }
 
 Value *llvm::emitFPutC(Value *Char, Value *File, IRBuilder<> &B,
                        const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::fputc))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[2];
-  AS[0] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::NoUnwind);
-  Constant *F;
-  if (File->getType()->isPointerTy())
-    F = M->getOrInsertFunction("fputc",
-                               AttributeSet::get(M->getContext(), AS),
-                               B.getInt32Ty(),
-                               B.getInt32Ty(), File->getType(),
-                               nullptr);
-  else
-    F = M->getOrInsertFunction("fputc",
-                               B.getInt32Ty(),
-                               B.getInt32Ty(),
+  Constant *F = M->getOrInsertFunction("fputc", B.getInt32Ty(), B.getInt32Ty(),
                                        File->getType(), nullptr);
+  if (File->getType()->isPointerTy())
+    inferLibFuncAttributes(*M->getFunction("fputc"), *TLI);
   Char = B.CreateIntCast(Char, B.getInt32Ty(), /*isSigned*/true,
                          "chari");
   CallInst *CI = B.CreateCall(F, {Char, File}, "fputc");
 
   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
     CI->setCallingConv(Fn->getCallingConv());
   return CI;
 }
 
 Value *llvm::emitFPutS(Value *Str, Value *File, IRBuilder<> &B,
                        const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::fputs))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[3];
-  AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
-  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::NoUnwind);
   StringRef FPutsName = TLI->getName(LibFunc::fputs);
-  Constant *F;
+  Constant *F = M->getOrInsertFunction(
+      FPutsName, B.getInt32Ty(), B.getInt8PtrTy(), File->getType(), nullptr);
   if (File->getType()->isPointerTy())
-    F = M->getOrInsertFunction(FPutsName,
-                               AttributeSet::get(M->getContext(), AS),
-                               B.getInt32Ty(),
-                               B.getInt8PtrTy(),
-                               File->getType(), nullptr);
-  else
-    F = M->getOrInsertFunction(FPutsName, B.getInt32Ty(),
-                               B.getInt8PtrTy(),
-                               File->getType(), nullptr);
+    inferLibFuncAttributes(*M->getFunction(FPutsName), *TLI);
   CallInst *CI = B.CreateCall(F, {castToCStr(Str, B), File}, "fputs");
 
   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
     CI->setCallingConv(Fn->getCallingConv());
   return CI;
 }
 
 Value *llvm::emitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder<> &B,
                         const DataLayout &DL, const TargetLibraryInfo *TLI) {
   if (!TLI->has(LibFunc::fwrite))
     return nullptr;
 
   Module *M = B.GetInsertBlock()->getModule();
-  AttributeSet AS[3];
-  AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
-  AS[1] = AttributeSet::get(M->getContext(), 4, Attribute::NoCapture);
-  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::NoUnwind);
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   StringRef FWriteName = TLI->getName(LibFunc::fwrite);
-  Constant *F;
-  if (File->getType()->isPointerTy())
-    F = M->getOrInsertFunction(
-        FWriteName, AttributeSet::get(M->getContext(), AS),
-        DL.getIntPtrType(Context), B.getInt8PtrTy(), DL.getIntPtrType(Context),
-        DL.getIntPtrType(Context), File->getType(), nullptr);
-  else
-    F = M->getOrInsertFunction(FWriteName, DL.getIntPtrType(Context),
-                               B.getInt8PtrTy(), DL.getIntPtrType(Context),
-                               DL.getIntPtrType(Context), File->getType(),
-                               nullptr);
+  Constant *F = M->getOrInsertFunction(
+      FWriteName, DL.getIntPtrType(Context), B.getInt8PtrTy(),
+      DL.getIntPtrType(Context), DL.getIntPtrType(Context), File->getType(),
+  if (File->getType()->isPointerTy())
+    inferLibFuncAttributes(*M->getFunction(FWriteName), *TLI);
   CallInst *CI =
       B.CreateCall(F, {castToCStr(Ptr, B), Size,
                        ConstantInt::get(DL.getIntPtrType(Context), 1), File});
 
   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
     CI->setCallingConv(Fn->getCallingConv());
   return CI;
 }