[clang] [llvm] [clang][CodeGen][AA] Introduce `!llvm.errno.tbaa` for errno alias disambiguation (PR #125258)

[John McCall via cfe-commits]

================
@@ -32,9 +32,9 @@ struct X f(void);
 // C11-O2-NEXT:    [[A:%.*]] = getelementptr inbounds nuw [[STRUCT_X]], ptr [[REF_TMP]], i32 0, i32 0
 // C11-O2-NEXT:    [[ARRAYDECAY:%.*]] = getelementptr inbounds [5 x i32], ptr [[A]], i64 0, i64 0
 // C11-O2-NEXT:    call void @llvm.lifetime.end.p0(i64 20, ptr [[REF_TMP]]) #[[ATTR5]]
-// C11-O2-NEXT:    store ptr [[ARRAYDECAY]], ptr [[P]], align 8, !tbaa [[TBAA2:![0-9]+]]
-// C11-O2-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P]], align 8, !tbaa [[TBAA2]]
-// C11-O2-NEXT:    [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4, !tbaa [[TBAA7:![0-9]+]]
+// C11-O2-NEXT:    store ptr [[ARRAYDECAY]], ptr [[P]], align 8, !tbaa [[TBAA6:![0-9]+]]
+// C11-O2-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P]], align 8, !tbaa [[TBAA6]]
+// C11-O2-NEXT:    [[TMP1:%.*]] = load i32, ptr [[TMP0]], align 4, !tbaa [[TBAA2:![0-9]+]]
----------------
rjmccall wrote:

Something like that would be great, because while I get why autogeneration is more than just a convenience, we do actually need to be reviewing autogenerated test changes, so spurious differences because autogen did something unstable is not a good use of reviewer time.

https://github.com/llvm/llvm-project/pull/125258