Index: include/llvm/Analysis/TargetLibraryInfo.h
===================================================================
--- include/llvm/Analysis/TargetLibraryInfo.h
+++ include/llvm/Analysis/TargetLibraryInfo.h
@@ -51,6 +51,7 @@
   unsigned char AvailableArray[(LibFunc::NumLibFuncs+3)/4];
   llvm::DenseMap<unsigned, std::string> CustomNames;
   static StringRef const StandardNames[LibFunc::NumLibFuncs];
+  bool ShouldExtI32Param, ShouldExtI32Return, ShouldSignExtI32Param;
 
   enum AvailabilityState {
     StandardName = 3, // (memset to all ones)
@@ -172,6 +173,26 @@
   ///
   /// Set VF to the vectorization factor.
   StringRef getScalarizedFunction(StringRef F, unsigned &VF) const;
+
+  /// Set to true iff i32 parameters to library functions should have signext
+  /// or zeroext attributes if they correspond to C-level int or unsigned int,
+  /// respectively.
+  void setShouldExtI32Param(bool Val) {
+    ShouldExtI32Param = Val;
+  }
+
+  /// Set to true iff i32 results from library functions should have signext
+  /// or zeroext attributes if they correspond to C-level int or unsigned int,
+  /// respectively.
+  void setShouldExtI32Return(bool Val) {
+    ShouldExtI32Return = Val;
+  }
+
+  /// Set to true iff i32 parameters to library functions should have signext
+  /// attribute if they correspond to C-level int or unsigned int.
+  void setShouldSignExtI32Param(bool Val) {
+    ShouldSignExtI32Param = Val;
+  }
 };
 
 /// Provides information about what library functions are available for
@@ -268,6 +289,26 @@
     return Impl->CustomNames.find(F)->second;
   }
 
+  /// Returns true iff i32 parameters to library functions should have
+  /// signext or zeroext attributes if they correspond to C-level int or
+  /// unsigned int, respectively.
+  bool shouldExtI32Param() const {
+    return Impl->ShouldExtI32Param;
+  }
+
+  /// Returns true iff i32 returns from library functions should have
+  /// signext or zeroext attributes if they correspond to C-level int or
+  /// unsigned int, respectively.
+  bool shouldExtI32Return() const {
+    return Impl->ShouldExtI32Return;
+  }
+
+  /// Returns true iff i32 parameters to library functions should have
+  /// signext attribute if they correspond to C-level int or unsigned int.
+  bool shouldSignExtI32Param() const {
+    return Impl->ShouldSignExtI32Param;
+  }
+
   /// Handle invalidation from the pass manager.
   ///
   /// If we try to invalidate this info, just return false. It cannot become
Index: lib/Analysis/TargetLibraryInfo.cpp
===================================================================
--- lib/Analysis/TargetLibraryInfo.cpp
+++ lib/Analysis/TargetLibraryInfo.cpp
@@ -414,6 +414,25 @@
   }
 
   TLI.addVectorizableFunctionsFromVecLib(ClVectorLibrary);
+
+  bool ShouldExtI32Param = false, ShouldExtI32Return = false,
+       ShouldSignExtI32Param = false;
+  // PowerPC64, Sparc64, SystemZ need signext/zeroext on i32 parameters and
+  // returns corresponding to C-level ints and unsigned ints.
+  if (T.getArch() == Triple::ppc64 || T.getArch() == Triple::ppc64le ||
+      T.getArch() == Triple::sparcv9 || T.getArch() == Triple::systemz) {
+    ShouldExtI32Param = true;
+    ShouldExtI32Return = true;
+  }
+  // Mips, on the other hand, needs signext on i32 parameters corresponding
+  // to both signed and unsigned ints.
+  if (T.getArch() == Triple::mips || T.getArch() == Triple::mipsel ||
+      T.getArch() == Triple::mips64 || T.getArch() == Triple::mips64el) {
+    ShouldSignExtI32Param = true;
+  }
+  TLI.setShouldExtI32Param(ShouldExtI32Param);
+  TLI.setShouldExtI32Return(ShouldExtI32Return);
+  TLI.setShouldSignExtI32Param(ShouldSignExtI32Param);
 }
 
 TargetLibraryInfoImpl::TargetLibraryInfoImpl() {
@@ -431,14 +450,19 @@
 }
 
 TargetLibraryInfoImpl::TargetLibraryInfoImpl(const TargetLibraryInfoImpl &TLI)
-    : CustomNames(TLI.CustomNames) {
+    : CustomNames(TLI.CustomNames), ShouldExtI32Param(TLI.ShouldExtI32Param),
+      ShouldExtI32Return(TLI.ShouldExtI32Return),
+      ShouldSignExtI32Param(TLI.ShouldSignExtI32Param) {
   memcpy(AvailableArray, TLI.AvailableArray, sizeof(AvailableArray));
   VectorDescs = TLI.VectorDescs;
   ScalarDescs = TLI.ScalarDescs;
 }
 
 TargetLibraryInfoImpl::TargetLibraryInfoImpl(TargetLibraryInfoImpl &&TLI)
-    : CustomNames(std::move(TLI.CustomNames)) {
+    : CustomNames(std::move(TLI.CustomNames)),
+      ShouldExtI32Param(TLI.ShouldExtI32Param),
+      ShouldExtI32Return(TLI.ShouldExtI32Return),
+      ShouldSignExtI32Param(TLI.ShouldSignExtI32Param) {
   std::move(std::begin(TLI.AvailableArray), std::end(TLI.AvailableArray),
             AvailableArray);
   VectorDescs = TLI.VectorDescs;
@@ -447,12 +471,18 @@
 
 TargetLibraryInfoImpl &TargetLibraryInfoImpl::operator=(const TargetLibraryInfoImpl &TLI) {
   CustomNames = TLI.CustomNames;
+  ShouldExtI32Param = TLI.ShouldExtI32Param;
+  ShouldExtI32Return = TLI.ShouldExtI32Return;
+  ShouldSignExtI32Param = TLI.ShouldSignExtI32Param;
   memcpy(AvailableArray, TLI.AvailableArray, sizeof(AvailableArray));
   return *this;
 }
 
 TargetLibraryInfoImpl &TargetLibraryInfoImpl::operator=(TargetLibraryInfoImpl &&TLI) {
   CustomNames = std::move(TLI.CustomNames);
+  ShouldExtI32Param = TLI.ShouldExtI32Param;
+  ShouldExtI32Return = TLI.ShouldExtI32Return;
+  ShouldSignExtI32Param = TLI.ShouldSignExtI32Param;
   std::move(std::begin(TLI.AvailableArray), std::end(TLI.AvailableArray),
             AvailableArray);
   return *this;