Index: lib/Transforms/Utils/BuildLibCalls.cpp
===================================================================
--- lib/Transforms/Utils/BuildLibCalls.cpp
+++ lib/Transforms/Utils/BuildLibCalls.cpp
@@ -116,6 +116,7 @@
   case LibFunc_wcslen:
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
+    Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setDoesNotCapture(F, 0);
     return Changed;
   case LibFunc_strchr:
Index: test/Transforms/InferFunctionAttrs/annotate.ll
===================================================================
--- test/Transforms/InferFunctionAttrs/annotate.ll
+++ test/Transforms/InferFunctionAttrs/annotate.ll
@@ -844,7 +844,7 @@
 ; CHECK: declare noalias i8* @strdup(i8* nocapture readonly) [[G0]]
 declare i8* @strdup(i8*)
 
-; CHECK: declare i64 @strlen(i8* nocapture) [[G1]]
+; CHECK: declare i64 @strlen(i8* nocapture) [[G2:#[0-9]+]]
 declare i64 @strlen(i8*)
 
 ; CHECK: declare i32 @strncasecmp(i8* nocapture, i8* nocapture, i64) [[G1]]
@@ -996,10 +996,11 @@
 
 
 ; memset_pattern16 isn't available everywhere.
-; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture, i8* nocapture readonly, i64) [[G2:#[0-9]+]]
+; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture, i8* nocapture readonly, i64) [[G3:#[0-9]+]]
 declare void @memset_pattern16(i8*, i8*, i64)
 
 
 ; CHECK: attributes [[G0]] = { nounwind }
 ; CHECK: attributes [[G1]] = { nounwind readonly }
-; CHECK-DARWIN: attributes [[G2]] = { argmemonly }
+; CHECK: attributes [[G2]] = { argmemonly nounwind readonly }
+; CHECK-DARWIN: attributes [[G3]] = { argmemonly }
Index: test/Transforms/LICM/strlen.ll
===================================================================
--- /dev/null
+++ test/Transforms/LICM/strlen.ll
@@ -0,0 +1,18 @@
+; RUN: opt < %s -inferattrs -licm | llvm-dis
+
+define void @test(i64* noalias %loc, i8* noalias %a) {
+; CHECK-LABEL: @test
+; CHECK: @strlen
+; CHECK-LABEL: loop:
+  br label %loop
+
+loop:
+  %res = call i64 @strlen(i8* %a)
+  store i64 %res, i64* %loc
+  br label %loop
+}
+
+; CHECK: attributes #0 = { argmemonly nounwind readonly }
+declare i64 @strlen(i8*)
+
+