[gcc/devel/omp/gcc-9] Backport r272993

[Tobias Burnus]

https://gcc.gnu.org/g:b098c7983c12e17ba872d2241173c186a3c6f4e9

commit b098c7983c12e17ba872d2241173c186a3c6f4e9
Author: Martin Liska <mliska@suse.cz>
Date:   Thu Jul 4 11:03:56 2019 +0200

    Backport r272993
    
    2019-07-04  Martin Liska  <mliska@suse.cz>
    
    	Backport from mainline
    	2019-07-03  Martin Liska  <mliska@suse.cz>
    
    	PR tree-optimization/90892
    	* builtins.c (inline_expand_builtin_string_cmp): Handle '\0'
    	in string constants.
    2019-07-04  Martin Liska  <mliska@suse.cz>
    
    	Backport from mainline
    	2019-07-03  Martin Liska  <mliska@suse.cz>
    
    	PR tree-optimization/90892
    	* gcc.dg/pr90892.c: New test.
    
    From-SVN: r273074

Diff:
---
 gcc/ChangeLog                  |  9 +++++++++
 gcc/builtins.c                 | 17 ++++++++++++++---
 gcc/testsuite/ChangeLog        |  8 ++++++++
 gcc/testsuite/gcc.dg/pr90892.c | 14 ++++++++++++++
 4 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ae63315..8201081 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -3,6 +3,15 @@
 	Backport from mainline
 	2019-07-03  Martin Liska  <mliska@suse.cz>
 
+	PR tree-optimization/90892
+	* builtins.c (inline_expand_builtin_string_cmp): Handle '\0'
+	in string constants.
+
+2019-07-04  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2019-07-03  Martin Liska  <mliska@suse.cz>
+
 	PR middle-end/90899
 	* multiple_target.c (create_dispatcher_calls): Add to comdat
 	group only if set for ifunc.
diff --git a/gcc/builtins.c b/gcc/builtins.c
index d37d73f..9bcb310 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -7124,8 +7124,19 @@ 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)
@@ -7140,7 +7151,7 @@ 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 2a42f3c..07b2fa7 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -3,6 +3,14 @@
 	Backport from mainline
 	2019-07-03  Martin Liska  <mliska@suse.cz>
 
+	PR tree-optimization/90892
+	* gcc.dg/pr90892.c: New test.
+
+2019-07-04  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2019-07-03  Martin Liska  <mliska@suse.cz>
+
 	PR middle-end/90899
 	* gcc.target/i386/pr90899.c: New test.
 
diff --git a/gcc/testsuite/gcc.dg/pr90892.c b/gcc/testsuite/gcc.dg/pr90892.c
new file mode 100644
index 0000000..e4b5310
--- /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;
+}