From: Jakub Jelinek <jakub@redhat.com>
Date: Wed, 7 May 2014 16:04:44 +0000 (+0200)
Subject: backport: re PR rtl-optimization/58365 (likely wrong code bug)
X-Git-Tag: releases/gcc-4.7.4~103
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dd5422383c749efd33b1e112a74a5b0ccb043f59;p=thirdparty%2Fgcc.git

backport: re PR rtl-optimization/58365 (likely wrong code bug)

	Backported from mainline
	2013-09-10  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/58365
	* cfgcleanup.c (merge_memattrs): Also clear MEM_READONLY_P
	resp. MEM_NOTRAP_P if they differ, or set MEM_VOLATILE_P if
	it differs.

	* gcc.c-torture/execute/pr58365.c: New test.

From-SVN: r210173
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 04f46d76a402..139a579103a8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,13 @@
 2014-05-07  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2013-09-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/58365
+	* cfgcleanup.c (merge_memattrs): Also clear MEM_READONLY_P
+	resp. MEM_NOTRAP_P if they differ, or set MEM_VOLATILE_P if
+	it differs.
+
 	2013-08-30  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/58277
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 6ff161425fe7..fae3aa656e57 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -922,6 +922,24 @@ merge_memattrs (rtx x, rtx y)
 	  set_mem_align (y, MEM_ALIGN (x));
 	}
     }
+  if (code == MEM)
+    {
+      if (MEM_READONLY_P (x) != MEM_READONLY_P (y))
+	{
+	  MEM_READONLY_P (x) = 0;
+	  MEM_READONLY_P (y) = 0;
+	}
+      if (MEM_NOTRAP_P (x) != MEM_NOTRAP_P (y))
+	{
+	  MEM_NOTRAP_P (x) = 0;
+	  MEM_NOTRAP_P (y) = 0;
+	}
+      if (MEM_VOLATILE_P (x) != MEM_VOLATILE_P (y))
+	{
+	  MEM_VOLATILE_P (x) = 1;
+	  MEM_VOLATILE_P (y) = 1;
+	}
+    }
 
   fmt = GET_RTX_FORMAT (code);
   for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b93701aa74f5..362317863b61 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2014-05-07  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2013-09-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/58365
+	* gcc.c-torture/execute/pr58365.c: New test.
+
 	2013-09-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/58325
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr58365.c b/gcc/testsuite/gcc.c-torture/execute/pr58365.c
new file mode 100644
index 000000000000..1e6079d8429a
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr58365.c
@@ -0,0 +1,35 @@
+/* PR rtl-optimization/58365 */
+
+extern void abort (void);
+
+struct S
+{
+  volatile int a;
+  int b, c, d, e;
+} f;
+static struct S g, h;
+int i = 1;
+
+char
+foo (void)
+{
+  return i;
+}
+
+static struct S
+bar (void)
+{
+  if (foo ())
+    return f;
+  return g;
+}
+
+int
+main ()
+{
+  h = bar ();
+  f.b = 1;
+  if (h.b != 0)
+    abort ();
+  return 0;
+}