diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -123,6 +123,7 @@
 
   // Set IO unlocked variants as unavailable
   // Set them as available per system below
+  TLI.setUnavailable(LibFunc_getc_unlocked);
   TLI.setUnavailable(LibFunc_getchar_unlocked);
   TLI.setUnavailable(LibFunc_putc_unlocked);
   TLI.setUnavailable(LibFunc_putchar_unlocked);
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
@@ -509,7 +509,9 @@
 ; CHECK: declare noundef i32 @getc(%opaque* nocapture noundef) [[NOFREE_NOUNWIND]]
 declare i32 @getc(%opaque*)
 
-; CHECK: declare noundef i32 @getc_unlocked(%opaque* nocapture noundef) [[NOFREE_NOUNWIND]]
+; CHECK-KNOWN: declare noundef i32 @getc_unlocked(%opaque* nocapture noundef) [[NOFREE_NOUNWIND]]
+; CHECK-UNKNOWN: declare i32 @getc_unlocked(%opaque*)
+; CHECK-UNKNOWN-NOT: #{{.*}}
 declare i32 @getc_unlocked(%opaque*)
 
 ; CHECK: declare noundef i32 @getchar() [[NOFREE_NOUNWIND]]