With delayed folding we added folding for arguments to various warning
functions, but that seems to be wrong for warn_tautological_cmp. In
general, it's a tricky call; probably better long run will be for the
warning functions to do their own folding if that's what they want.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 941058d18590e5c524ca97ad57f9ffdfcfec0469
Author: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Sat Nov 14 18:54:16 2015 +0000
PR bootstrap/68346
* call.c (build_new_op_1): Don't fold arguments to
warn_tautological_cmp.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230382 138bc75d-0d04-0410-961f-82ee72b054a4
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 77c2936..8cdda62 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -5741,7 +5741,7 @@ build_new_op_1 (location_t loc, enum tree_code code, int flags, tree arg1,
maybe_warn_bool_compare (loc, code, fold (arg1),
fold (arg2));
if (complain & tf_warning && warn_tautological_compare)
- warn_tautological_cmp (loc, code, fold (arg1), fold (arg2));
+ warn_tautological_cmp (loc, code, arg1, arg2);
/* Fall through. */
case PLUS_EXPR:
case MINUS_EXPR:
diff --git a/gcc/testsuite/g++.dg/warn/Wtautological-compare.C b/gcc/testsuite/g++.dg/warn/Wtautological-compare.C
new file mode 100644
index 0000000..451fd54
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wtautological-compare.C
@@ -0,0 +1,7 @@
+// PR bootstrap/68346
+// { dg-options -Wtautological-compare }
+
+bool f(unsigned u)
+{
+ return ((unsigned)(int)u == u);
+}
