ScalarEvolution: Warn if the result of setFlags/clearFlags is unused.

This was a source of bugs in the past.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194929 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 944b1447b456228c5f35c936124a69af4396ed80..d7f617817179892bcd6ca5fe4a94dce188631bac 100644 (file)
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -189,15 +189,16 @@ namespace llvm {
 
     /// Convenient NoWrapFlags manipulation that hides enum casts and is
     /// visible in the ScalarEvolution name space.
-    static SCEV::NoWrapFlags maskFlags(SCEV::NoWrapFlags Flags, int Mask) {
+    static SCEV::NoWrapFlags LLVM_ATTRIBUTE_UNUSED_RESULT
+    maskFlags(SCEV::NoWrapFlags Flags, int Mask) {
       return (SCEV::NoWrapFlags)(Flags & Mask);
     }
-    static SCEV::NoWrapFlags setFlags(SCEV::NoWrapFlags Flags,
-                                      SCEV::NoWrapFlags OnFlags) {
+    static SCEV::NoWrapFlags LLVM_ATTRIBUTE_UNUSED_RESULT
+    setFlags(SCEV::NoWrapFlags Flags, SCEV::NoWrapFlags OnFlags) {
       return (SCEV::NoWrapFlags)(Flags | OnFlags);
     }
-    static SCEV::NoWrapFlags clearFlags(SCEV::NoWrapFlags Flags,
-                                        SCEV::NoWrapFlags OffFlags) {
+    static SCEV::NoWrapFlags LLVM_ATTRIBUTE_UNUSED_RESULT
+    clearFlags(SCEV::NoWrapFlags Flags, SCEV::NoWrapFlags OffFlags) {
       return (SCEV::NoWrapFlags)(Flags & ~OffFlags);
     }