Add an APValue representation for the difference between two address-of-label expressions. Add support to Evaluate and CGExprConstant for generating/handling them. Remove the special-case for such differences in Expr::isConstantInitializer.
With that done, remove a bunch of buggy code from CGExprConstant for handling scalar expressions which is no longer necessary.
Fixes PR11705.
llvm-svn: 147561
diff --git a/clang/test/CodeGenCXX/const-init.cpp b/clang/test/CodeGenCXX/const-init.cpp
index aa77d5c..6fabfc7 100644
--- a/clang/test/CodeGenCXX/const-init.cpp
+++ b/clang/test/CodeGenCXX/const-init.cpp
@@ -56,3 +56,16 @@
const MutableMember MM = { 0 };
return ++MM.n;
}
+
+// Make sure we don't try to fold this in the frontend; the backend can't
+// handle it.
+// CHECK: @PR11705 = global i128 0
+__int128_t PR11705 = (__int128_t)&PR11705;
+
+// Make sure we don't try to fold this either.
+// CHECK: @_ZZ23UnfoldableAddrLabelDiffvE1x = internal global i128 0
+void UnfoldableAddrLabelDiff() { static __int128_t x = (long)&&a-(long)&&b; a:b:return;}
+
+// But make sure we do fold this.
+// CHECK: @_ZZ21FoldableAddrLabelDiffvE1x = internal global i64 sub (i64 ptrtoint (i8* blockaddress(@_Z21FoldableAddrLabelDiffv, %a)
+void FoldableAddrLabelDiff() { static long x = (long)&&a-(long)&&b; a:b:return;}