On 6/18/19 12:16 PM, Jakub Jelinek wrote:
> I think any such length changes should be moved after the two punt checks.
> Move also the len3 setting before the new checks (of course conditional on
> is_ncmp).
Ok, I'm sending updated version of the patch that addresses this.
I've been testing the patch.
Ready to be installed then?
Thanks,
Martin
>From 35043ab431c0dc1e8dcda484725a1f8875a4b95b 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 | 17 ++++++++++++++---
gcc/testsuite/gcc.dg/pr90892.c | 14 ++++++++++++++
2 files changed, 28 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/pr90892.c
diff --git a/gcc/builtins.c b/gcc/builtins.c
index c53afe8b033..db7939cfde8 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -7118,8 +7118,19 @@ inline_expand_builtin_string_cmp (tree exp, rtx target)
return NULL_RTX;
/* For strncmp, if the length is not a const, not qualify. */
- if (is_ncmp && !tree_fits_uhwi_p (len3_tree))
- return NULL_RTX;
+ if (is_ncmp)
+ {
+ if (!tree_fits_uhwi_p (len3_tree))
+ return NULL_RTX;
+ else
+ len3 = tree_to_uhwi (len3_tree);
+ }
+
+ if (src_str1 != NULL)
+ len1 = strnlen (src_str1, len1) + 1;
+
+ if (src_str2 != NULL)
+ len2 = strnlen (src_str2, len2) + 1;
int const_str_n = 0;
if (!len1)
@@ -7134,7 +7145,7 @@ inline_expand_builtin_string_cmp (tree exp, rtx target)
gcc_checking_assert (const_str_n > 0);
length = (const_str_n == 1) ? len1 : len2;
- if (is_ncmp && (len3 = tree_to_uhwi (len3_tree)) < length)
+ if (is_ncmp && len3 < length)
length = len3;
/* If the length of the comparision is larger than the threshold,
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
