diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -105,14 +105,18 @@
   return true;
 }
 
-static bool setRetAndArgsNoUndef(Function &F) {
-  bool Changed = false;
+static bool setRetNoUndef(Function &F) {
   if (!F.getReturnType()->isVoidTy() &&
       !F.hasAttribute(AttributeList::ReturnIndex, Attribute::NoUndef)) {
     F.addAttribute(AttributeList::ReturnIndex, Attribute::NoUndef);
     ++NumNoUndef;
-    Changed = true;
+    return true;
   }
+  return false;
+}
+
+static bool setArgsNoUndef(Function &F) {
+  bool Changed = false;
   for (unsigned ArgNo = 0; ArgNo < F.arg_size(); ++ArgNo) {
     if (!F.hasParamAttribute(ArgNo, Attribute::NoUndef)) {
       F.addParamAttr(ArgNo, Attribute::NoUndef);
@@ -123,6 +127,10 @@
   return Changed;
 }
 
+static bool setRetAndArgsNoUndef(Function &F) {
+  return setRetNoUndef(F) | setArgsNoUndef(F);
+}
+
 static bool setRetNonNull(Function &F) {
   assert(F.getReturnType()->isPointerTy() &&
          "nonnull applies only to pointers");
@@ -318,6 +326,7 @@
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_malloc:
+    Changed |= setRetNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
@@ -383,10 +392,14 @@
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_realloc:
+    Changed |= setRetNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
+  case LibFunc_reallocf:
+    Changed |= setRetNoUndef(F);
+    return Changed;
   case LibFunc_read:
     // May throw; "read" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
@@ -427,6 +440,7 @@
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_aligned_alloc:
+    Changed |= setRetNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
@@ -448,6 +462,7 @@
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_calloc:
+    Changed |= setRetNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
@@ -501,6 +516,7 @@
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_free:
+    Changed |= setArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
@@ -723,6 +739,7 @@
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
   case LibFunc_valloc:
+    Changed |= setRetNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
@@ -891,6 +908,7 @@
   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 |= setRetNoUndef(F);
     Changed |= setRetNonNull(F);
     Changed |= setRetDoesNotAlias(F);
     return Changed;
diff --git a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
--- a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
+++ b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
@@ -6,9 +6,9 @@
 
 ; operator new routines
 declare i8* @_Znwj(i64 )
-; CHECK: declare noalias nonnull i8* @_Znwj(i64) [[G0:#[0-9]+]]
+; CHECK: declare noalias noundef nonnull i8* @_Znwj(i64) [[G0:#[0-9]+]]
 declare i8* @_Znwm(i64)
-; CHECK: declare noalias nonnull i8* @_Znwm(i64) [[G0]]
+; CHECK: declare noalias noundef nonnull i8* @_Znwm(i64) [[G0]]
 
 declare i32 @__nvvm_reflect(i8*)
 ; CHECK-NVPTX: declare noundef i32 @__nvvm_reflect(i8* noundef) [[G0:#[0-9]+]]
@@ -253,7 +253,7 @@
 ; CHECK: declare void @bzero(i8* nocapture, i64) [[G1]]
 declare void @bzero(i8*, i64)
 
-; CHECK: declare noalias i8* @calloc(i64, i64) [[G1]]
+; CHECK: declare noalias noundef i8* @calloc(i64, i64) [[G1]]
 declare i8* @calloc(i64, i64)
 
 ; CHECK: declare double @cbrt(double) [[G0]]
@@ -451,7 +451,7 @@
 ; CHECK: declare noundef i64 @fread(i8* nocapture noundef, i64 noundef, i64 noundef, %opaque* nocapture noundef) [[G1]]
 declare i64 @fread(i8*, i64, i64, %opaque*)
 
-; CHECK: declare void @free(i8* nocapture) [[G3:#[0-9]+]]
+; CHECK: declare void @free(i8* nocapture noundef) [[G3:#[0-9]+]]
 declare void @free(i8*)
 
 ; CHECK: declare double @frexp(double, i32* nocapture) [[G1]]
@@ -613,7 +613,7 @@
 ; CHECK-LINUX: declare noundef i32 @lstat64(i8* nocapture noundef readonly, %opaque* nocapture noundef) [[G1]]
 declare i32 @lstat64(i8*, %opaque*)
 
-; CHECK: declare noalias i8* @malloc(i64) [[G1]]
+; CHECK: declare noalias noundef i8* @malloc(i64) [[G1]]
 declare i8* @malloc(i64)
 
 ; CHECK-LINUX: declare noalias i8* @memalign(i64, i64) [[G0]]
@@ -726,10 +726,10 @@
 ; CHECK: declare noundef i64 @readlink(i8* nocapture noundef readonly, i8* nocapture noundef, i64 noundef) [[G1]]
 declare i64 @readlink(i8*, i8*, i64)
 
-; CHECK: declare noalias i8* @realloc(i8* nocapture, i64) [[G3]]
+; CHECK: declare noalias noundef i8* @realloc(i8* nocapture, i64) [[G3]]
 declare i8* @realloc(i8*, i64)
 
-; CHECK: declare i8* @reallocf(i8*, i64)
+; CHECK: declare noundef i8* @reallocf(i8*, i64)
 declare i8* @reallocf(i8*, i64)
 
 ; CHECK: declare noundef i8* @realpath(i8* nocapture noundef readonly, i8* noundef) [[G1]]
@@ -978,7 +978,7 @@
 ; CHECK: declare noundef i32 @utimes(i8* nocapture noundef readonly, %opaque* nocapture noundef readonly) [[G1]]
 declare i32 @utimes(i8*, %opaque*)
 
-; CHECK: declare noalias i8* @valloc(i64) [[G1]]
+; CHECK: declare noalias noundef i8* @valloc(i64) [[G1]]
 declare i8* @valloc(i64)
 
 ; CHECK: declare noundef i32 @vfprintf(%opaque* nocapture noundef, i8* nocapture noundef readonly, %opaque* noundef) [[G1]]