From: Richard Biener <rguenther@suse.de>
Date: Fri, 26 Feb 2016 08:34:58 +0000 (+0000)
Subject: re PR target/69551 (Wrong code with single element vector insert)
X-Git-Tag: basepoints/gcc-7~750
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5aed7e2c0d9bde14f5c0e45e3d29727e6ec94324;p=thirdparty%2Fgcc.git

re PR target/69551 (Wrong code with single element vector insert)

2016-02-26  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/69551
	* tree-ssa-structalias.c (get_constraint_for_ssa_var): When
	looking through aliases adjust DECL_PT_UID to refer to the
	ultimate alias target.

	* gcc.dg/torture/pr69951.c: New testcase.

From-SVN: r233734
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0414e0970130..c4aa8c04a55d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2016-02-26  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/69551
+	* tree-ssa-structalias.c (get_constraint_for_ssa_var): When
+	looking through aliases adjust DECL_PT_UID to refer to the
+	ultimate alias target.
+
 2016-02-25  Martin Liska  <mliska@suse.cz>
 
 	PR middle-end/69919
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2e45a6a0b6cc..5fdc3e354895 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-02-26  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/69551
+	* gcc.dg/torture/pr69951.c: New testcase.
+
 2016-02-25  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/48795
diff --git a/gcc/testsuite/gcc.dg/torture/pr69951.c b/gcc/testsuite/gcc.dg/torture/pr69951.c
new file mode 100644
index 000000000000..cb46fefccdb2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr69951.c
@@ -0,0 +1,21 @@
+/* { dg-do run } */
+/* { dg-require-alias "" } */
+
+extern void abort (void);
+
+int a = 1, c = 1;
+extern int b __attribute__((alias("a")));
+extern int d __attribute__((alias("c")));
+int main(int argc)
+{
+  int *p, *q;
+  if (argc)
+    p = &c, q = &d;
+  else
+    p = &b, q = &d;
+  *p = 1;
+  *q = 2;
+  if (*p == 1)
+    abort();
+  return 0;
+}
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index d7a7dc554e4d..de123800f0b3 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -2943,6 +2943,14 @@ get_constraint_for_ssa_var (tree t, vec<ce_s> *results, bool address_p)
       if (node && node->alias && node->analyzed)
 	{
 	  node = node->ultimate_alias_target ();
+	  /* Canonicalize the PT uid of all aliases to the ultimate target.
+	     ???  Hopefully the set of aliases can't change in a way that
+	     changes the ultimate alias target.  */
+	  gcc_assert ((! DECL_PT_UID_SET_P (node->decl)
+		       || DECL_PT_UID (node->decl) == DECL_UID (node->decl))
+		      && (! DECL_PT_UID_SET_P (t)
+			  || DECL_PT_UID (t) == DECL_UID (node->decl)));
+	  DECL_PT_UID (t) = DECL_UID (node->decl);
 	  t = node->decl;
 	}
     }