From: Martin Liska <mliska@suse.cz>
Date: Wed, 3 Jul 2019 08:32:25 +0000 (+0200)
Subject: Handle '\0' in strcmp in RTL expansion (PR tree-optimization/90892).
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6aa2e42cb4be16ee0937ba872b297b11d8f0a18b;p=gcc.git

Handle '\0' in strcmp in RTL expansion (PR tree-optimization/90892).

2019-07-03  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/90892
	* builtins.c (inline_expand_builtin_string_cmp): Handle '\0'
	in string constants.
2019-07-03  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/90892
	* gcc.dg/pr90892.c: New test.

From-SVN: r272993
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f2f69905f76..a1d7c5bedd7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-03  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/90892
+	* builtins.c (inline_expand_builtin_string_cmp): Handle '\0'
+	in string constants.
+
 2019-07-03  Martin Liska  <mliska@suse.cz>
 
 	PR middle-end/90899
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 2b8914f13ee..e2ba356c0d3 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/ChangeLog b/gcc/testsuite/ChangeLog
index 512e86cf2cb..d5521123230 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-07-03  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/90892
+	* gcc.dg/pr90892.c: New test.
+
 2019-07-03  Martin Liska  <mliska@suse.cz>
 
 	PR middle-end/90899
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;
+}