On 8/10/21 3:45 AM, Richard Biener wrote:
On Mon, Aug 9, 2021 at 10:31 PM Andrew MacLeod via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
The user has overridden the function name "toupper" . Its marked as a
builtin function, presumably because it matches the name. In range
folding, we were assuming the LHS and the parameter were compatible
types... but they are not in this case..
I don't know if we should be marking such a thing as a builtin function,
but regardless.. we shouldn't be trapping. If the type of the argument
is not compatible with the LHS, then we'll simply assume nothing about
the function.
Bootstraps with no regression on x86_64-pc-linux-gnu. pushed.
I wonder why the gimple_call_combined_fn verification
using gimple_builtin_call_types_compatible_p isn't enough here?
Yes, it's matching is a bit lazy, but only with respect to promotion
of arguments to 'int'.
Richard.
I set a breakpoint on the return type field for the builtin... A quick
check shows the return type of the builtin is being changed to "unsigned
int" here:
#0 merge_decls (newdecl=0x7fffe9f67100, olddecl=0x7fffe9ed2100,
newtype=0x7fffe9e3ae70, oldtype=0x7fffe9e3ae70) at
/gcc/master/gcc/gcc/c/c-decl.c:2598
#1 0x0000000000a0628d in duplicate_decls (newdecl=0x7fffe9f67100,
olddecl=0x7fffe9ed2100) at /gcc/master/gcc/gcc/c/c-decl.c:2963
#2 0x0000000000a07464 in pushdecl (x=0x7fffe9f67100) at
/gcc/master/gcc/gcc/c/c-decl.c:3256
#3 0x0000000000a1d113 in start_function (declspecs=0x37728b0,
declarator=0x3772ae0, attributes=0x0) at /gcc/master/gcc/gcc/c/c-decl.c:9644
#4 0x0000000000a8667c in c_parser_declaration_or_fndef
(parser=0x7ffff7ff7ab0, fndef_ok=true, static_assert_ok=true,
empty_ok=true, nested=false, start_attr_ok=true,
objc_foreach_object_declaration=0x0,
omp_declare_simd_clauses=0x0, have_attrs=false, attrs=0x0,
oacc_routine_data=0x0, fallthru_attr_p=0x0) at
/gcc/master/gcc/gcc/c/c-parser.c:2444
It would appear that merge_decls is merging the olddecl (the bultin)
with newdecl and results in changing the LHS to unsigned int, so now it
thinks the builtin matches. eeeks.
I don't know what the correct thing to do is, but a quick hack to check
if old_decl is a builtin and return false from duplicate_decl also seems
to resolve the problem:
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 221a67fe57b..27ab6ac9f1a 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -2960,6 +2960,9 @@ duplicate_decls (tree newdecl, tree olddecl)
return false;
}
+ if (DECL_BUILT_IN_CLASS (olddecl) != NOT_BUILT_IN)
+ return false;
+
merge_decls (newdecl, olddecl, newtype, oldtype);
/* The NEWDECL will no longer be needed.
