On 6/18/19 10:23 AM, Martin Liška wrote:
> On 6/18/19 10:11 AM, Jakub Jelinek wrote:
>> On Tue, Jun 18, 2019 at 10:07:50AM +0200, Martin Liška wrote:
>>> diff --git a/gcc/builtins.c b/gcc/builtins.c
>>> index 3463ffb1539..b58e1e58d4d 100644
>>> --- a/gcc/builtins.c
>>> +++ b/gcc/builtins.c
>>> @@ -7142,6 +7142,20 @@ inline_expand_builtin_string_cmp (tree exp, rtx
>>> target)
>>> const char *src_str1 = c_getstr (arg1, &len1);
>>> const char *src_str2 = c_getstr (arg2, &len2);
>>>
>>> + if (src_str1 != NULL)
>>> + {
>>> + unsigned HOST_WIDE_INT str_str1_strlen = strnlen (src_str1, len1);
>>> + if (str_str1_strlen + 1 < len1)
>>> + len1 = str_str1_strlen + 1;
>>
>> You really don't need any of this after strnlen. strnlen is already
>> guaranteed to return a number from 0 to len1 inclusive, so you can really
>> just do:
>> if (src_str1 != NULL)
>> len1 = strnlen (src_str1, len1);
>>
>> Jakub
>>
>
> Got it, I'm testing that.
>
> Martin
>
Ok, there's an off-by-one error in the previous patch candidate.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
>From fe4ef7d43c506f450de802a7d8a602fab7da4545 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Mon, 17 Jun 2019 10:39:15 +0200
Subject: [PATCH] Handle '\0' in strcmp in RTL expansion (PR
tree-optimization/90892).
gcc/ChangeLog:
2019-06-17 Martin Liska <mli...@suse.cz>
PR tree-optimization/90892
* builtins.c (inline_expand_builtin_string_cmp): Handle '\0'
in string constants.
gcc/testsuite/ChangeLog:
2019-06-17 Martin Liska <mli...@suse.cz>
PR tree-optimization/90892
* gcc.dg/pr90892.c: New test.
---
gcc/builtins.c | 6 ++++++
gcc/testsuite/gcc.dg/pr90892.c | 14 ++++++++++++++
2 files changed, 20 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr90892.c
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 3463ffb1539..78a4bec9bd0 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -7142,6 +7142,12 @@ inline_expand_builtin_string_cmp (tree exp, rtx target)
const char *src_str1 = c_getstr (arg1, &len1);
const char *src_str2 = c_getstr (arg2, &len2);
+ if (src_str1 != NULL)
+ len1 = strnlen (src_str1, len1) + 1;
+
+ if (src_str2 != NULL)
+ len2 = strnlen (src_str2, len2) + 1;
+
/* If neither strings is constant string, the call is not qualify. */
if (!src_str1 && !src_str2)
return NULL_RTX;
diff --git a/gcc/testsuite/gcc.dg/pr90892.c b/gcc/testsuite/gcc.dg/pr90892.c
new file mode 100644
index 00000000000..e4b5310807a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr90892.c
@@ -0,0 +1,14 @@
+/* PR tree-optimization/90892 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+const char *a = "A\0b";
+
+int
+main()
+{
+ if (__builtin_strncmp(a, "A\0", 2) != 0)
+ __builtin_abort ();
+
+ return 0;
+}
--
2.21.0
