[TLI] Unify LibFunc attribute inference. NFCI.

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.

The next step is to have something like getOrInsertLibFunc that also
sets the attributes.

Differential Revision: http://reviews.llvm.org/D19470

llvm-svn: 267759

1 files changed, 5 insertions, 685 deletions

diff --git a/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp b/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
index 3c46c49..ab2d2bd 100644
--- a/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
@@ -8,7 +8,6 @@
 //===----------------------------------------------------------------------===//
 
 #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"
@@ -16,699 +15,20 @@
 #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;
 }