2 files changed, 21 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 2be5d5caf7c..b12778278ce 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -349,6 +349,9 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
     TLI.setUnavailable(LibFunc_atoll);
     TLI.setUnavailable(LibFunc_frexpf);
     TLI.setUnavailable(LibFunc_llabs);
+
+    // Win32 does *not* provide pthread_self.
+    TLI.setUnavailable(LibFunc_pthread_self);
   }
 
   switch (T.getOS()) {
@@ -1263,6 +1266,12 @@ bool TargetLibraryInfoImpl::isValidProtoForLibFunc(const FunctionType &FTy,
             FTy.getParamType(0)->isPointerTy() &&
             FTy.getParamType(1) == SizeTTy && FTy.getParamType(2) == SizeTTy);
 
+  // We do not attempt to match the return value here. i.e. thread identifiers
+  // should be considered opaque, for example, representation using either an
+  // arithmetic type or a structure is permitted. 
+  case LibFunc_pthread_self:
+    return NumParams == 0;
+
   case LibFunc_wcslen:
     return (NumParams == 1 && FTy.getParamType(0)->isPointerTy() &&
             FTy.getReturnType()->isIntegerTy());
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index ebde1f9a17d..cf345325254 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -38,6 +38,7 @@ 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");
+STATISTIC(NumSpeculatable, "Number of functions inferred as speculatable");
 
 static bool setDoesNotAccessMemory(Function &F) {
   if (F.doesNotAccessMemory())
@@ -71,6 +72,14 @@ static bool setDoesNotThrow(Function &F) {
   return true;
 }
 
+static bool setSpeculatable(Function &F) {
+  if (F.isSpeculatable())
+    return false;
+  F.setSpeculatable();
+  ++NumSpeculatable;
+  return true;
+}
+
 static bool setRetDoesNotAlias(Function &F) {
   if (F.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias))
     return false;
@@ -530,6 +539,9 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
+  case LibFunc_pthread_self:
+    Changed |= setSpeculatable(F);
+    return Changed;
   case LibFunc_vfscanf:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);