[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, 718 insertions, 110 deletions

diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index 40339cc748e..f801fd4168f 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -13,6 +13,7 @@
 
 #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"
@@ -25,6 +26,687 @@
 
 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");
@@ -36,15 +718,10 @@ Value *llvm::emitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout &DL,
     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());
@@ -58,16 +735,11 @@ Value *llvm::emitStrChr(Value *Ptr, char C, IRBuilder<> &B,
     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()))
@@ -81,16 +753,11 @@ Value *llvm::emitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilder<> &B,
     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");
 
@@ -106,14 +773,9 @@ Value *llvm::emitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
     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()))
@@ -127,16 +789,10 @@ Value *llvm::emitStrNCpy(Value *Dst, Value *Src, Value *Len, IRBuilder<> &B,
     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()))
@@ -173,13 +829,11 @@ Value *llvm::emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilder<> &B,
     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()))
@@ -194,16 +848,11 @@ Value *llvm::emitMemCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilder<> &B,
     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");
 
@@ -286,16 +935,9 @@ Value *llvm::emitPutS(Value *Str, IRBuilder<> &B,
     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());
@@ -308,22 +950,10 @@ Value *llvm::emitFPutC(Value *Char, Value *File, IRBuilder<> &B,
     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;
+  Constant *F = M->getOrInsertFunction("fputc", B.getInt32Ty(), B.getInt32Ty(),
+                                       File->getType(), nullptr);
   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(),
-                               File->getType(), nullptr);
+    inferLibFuncAttributes(*M->getFunction("fputc"), *TLI);
   Char = B.CreateIntCast(Char, B.getInt32Ty(), /*isSigned*/true,
                          "chari");
   CallInst *CI = B.CreateCall(F, {Char, File}, "fputc");
@@ -339,23 +969,11 @@ Value *llvm::emitFPutS(Value *Str, Value *File, IRBuilder<> &B,
     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()))
@@ -369,24 +987,14 @@ Value *llvm::emitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder<> &B,
     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;
+  Constant *F = M->getOrInsertFunction(
+      FWriteName, DL.getIntPtrType(Context), B.getInt8PtrTy(),
+      DL.getIntPtrType(Context), DL.getIntPtrType(Context), File->getType(),
+      nullptr);
   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);
+    inferLibFuncAttributes(*M->getFunction(FWriteName), *TLI);
   CallInst *CI =
       B.CreateCall(F, {castToCStr(Ptr, B), Size,
                        ConstantInt::get(DL.getIntPtrType(Context), 1), File});