On 10/27/2016 03:35 PM, Richard Biener wrote:
> On Thu, Oct 27, 2016 at 9:41 AM, Martin Liška <mli...@suse.cz> wrote:
>> Running simple test-case w/o the proper header file causes ICE:
>> strncmp ("a", "b", -1);
>>
>> 0xe74462 tree_to_uhwi(tree_node const*)
>> ../../gcc/tree.c:7324
>> 0x90a23f host_size_t_cst_p
>> ../../gcc/fold-const-call.c:63
>> 0x90a23f fold_const_call(combined_fn, tree_node*, tree_node*, tree_node*,
>> tree_node*)
>> ../../gcc/fold-const-call.c:1512
>> 0x787b01 fold_builtin_3
>> ../../gcc/builtins.c:8385
>> 0x787b01 fold_builtin_n(unsigned int, tree_node*, tree_node**, int, bool)
>> ../../gcc/builtins.c:8465
>> 0x9052b1 fold(tree_node*)
>> ../../gcc/fold-const.c:11919
>> 0x6de2bb c_fully_fold_internal
>> ../../gcc/c/c-fold.c:185
>> 0x6e1f6b c_fully_fold(tree_node*, bool, bool*)
>> ../../gcc/c/c-fold.c:90
>> 0x67cbbf c_process_expr_stmt(unsigned int, tree_node*)
>> ../../gcc/c/c-typeck.c:10369
>> 0x67cfbd c_finish_expr_stmt(unsigned int, tree_node*)
>> ../../gcc/c/c-typeck.c:10414
>> 0x6cb578 c_parser_statement_after_labels
>> ../../gcc/c/c-parser.c:5430
>> 0x6cd333 c_parser_compound_statement_nostart
>> ../../gcc/c/c-parser.c:4944
>> 0x6cdbde c_parser_compound_statement
>> ../../gcc/c/c-parser.c:4777
>> 0x6c93ac c_parser_declaration_or_fndef
>> ../../gcc/c/c-parser.c:2176
>> 0x6d51ab c_parser_external_declaration
>> ../../gcc/c/c-parser.c:1574
>> 0x6d5c09 c_parser_translation_unit
>> ../../gcc/c/c-parser.c:1454
>> 0x6d5c09 c_parse_file()
>> ../../gcc/c/c-parser.c:18173
>> 0x72ffd2 c_common_parse_file()
>> ../../gcc/c-family/c-opts.c:1087
>>
>> Following patch improves the host_size_t_cst_p predicate.
>>
>> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
>>
>> Ready to be installed?
>
> I believe the wi::min_precision (t, UNSIGNED) <= sizeof (size_t) *
> CHAR_BIT test is now redundant.
>
> OTOH it was probably desired to allow -1 here? A little looking back
> in time should tell.
Ok, it started with r229922, where it was changed from:
if (tree_fits_uhwi_p (len) && p1 && p2)
{
const int i = strncmp (p1, p2, tree_to_uhwi (len));
...
to current version:
case CFN_BUILT_IN_STRNCMP:
{
bool const_size_p = host_size_t_cst_p (arg2, &s2);
Thus I'm suggesting to change to back to it.
Ready to be installed?
Thanks,
Martin
>
> Richard.
>
>> Martin
>From 608ed3ac6b743846e9bce62cd0b0e83e2b018684 Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Wed, 26 Oct 2016 13:48:39 +0200
Subject: [PATCH] Fix host_size_t_cst_p predicat
gcc/ChangeLog:
2016-10-26 Martin Liska <mli...@suse.cz>
* fold-const-call.c (host_size_t_cst_p): Test whether
it can fit to uhwi.
gcc/testsuite/ChangeLog:
2016-10-26 Martin Liska <mli...@suse.cz>
* gcc.dg/tree-ssa/builtins-folding-gimple-ub.c (main): Add
test case.
---
gcc/fold-const-call.c | 3 +--
gcc/testsuite/gcc.dg/tree-ssa/builtins-folding-gimple-ub.c | 4 ++++
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/gcc/fold-const-call.c b/gcc/fold-const-call.c
index 05a15f9..b8154c8 100644
--- a/gcc/fold-const-call.c
+++ b/gcc/fold-const-call.c
@@ -57,8 +57,7 @@ complex_cst_p (tree t)
static inline bool
host_size_t_cst_p (tree t, size_t *size_out)
{
- if (integer_cst_p (t)
- && wi::min_precision (t, UNSIGNED) <= sizeof (size_t) * CHAR_BIT)
+ if (tree_fits_uhwi_p (t))
{
*size_out = tree_to_uhwi (t);
return true;
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/builtins-folding-gimple-ub.c b/gcc/testsuite/gcc.dg/tree-ssa/builtins-folding-gimple-ub.c
index df0ede2..e1658d1 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/builtins-folding-gimple-ub.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/builtins-folding-gimple-ub.c
@@ -17,6 +17,10 @@ main (void)
if (__builtin_memchr (foo1, 'x', 1000)) /* Not folded away. */
__builtin_abort ();
+ /* STRNCMP. */
+ if (strncmp ("a", "b", -1)) /* { dg-warning "implicit declaration of function" } */
+ __builtin_abort ();
+
return 0;
}
--
2.10.1
