From: Eric Botcazou <ebotcazou@adacore.com>
Date: Sun, 31 Jan 2010 21:08:15 +0000 (+0000)
Subject: re PR middle-end/42898 (volatile structures and compound literal initializers)
X-Git-Tag: releases/gcc-4.3.5~195
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e023c7b0a0a101ea88a21cdd2d249a17adc8dcd1;p=thirdparty%2Fgcc.git

re PR middle-end/42898 (volatile structures and compound literal initializers)

2010-01-31  Eric Botcazou  <ebotcazou@adacore.com>

	PR middle-end/42898
	Backport from mainline:
	2009-04-23  Eric Botcazou  <ebotcazou@adacore.com>

	* gimplify.c (gimplify_modify_expr_rhs) <VAR_DECL>: Do not do a direct
	assignment from the constructor either if the target is volatile.

From-SVN: r156416
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e05c1fd7c699..67438610a930 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2010-01-31  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/42898
+	Backport from mainline:
+	2009-04-23  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gimplify.c (gimplify_modify_expr_rhs) <VAR_DECL>: Do not do a direct
+	assignment from the constructor either if the target is volatile.
+
 2010-01-31  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/42898
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 71af972b2659..897c185c1437 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -3566,11 +3566,14 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p,
     switch (TREE_CODE (*from_p))
       {
       case VAR_DECL:
-	/* If we're assigning from a constant constructor, move the
-	   constructor expression to the RHS of the MODIFY_EXPR.  */
+	/* If we're assigning from a read-only variable initialized with
+	   a constructor, do the direct assignment from the constructor,
+	   but only if neither source nor target are volatile since this
+	   latter assignment might end up being done on a per-field basis.  */
 	if (DECL_INITIAL (*from_p)
 	    && TREE_READONLY (*from_p)
 	    && !TREE_THIS_VOLATILE (*from_p)
+	    && !TREE_THIS_VOLATILE (*to_p)
 	    && TREE_CODE (DECL_INITIAL (*from_p)) == CONSTRUCTOR)
 	  {
 	    tree old_from = *from_p;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 000461bc853d..ca235f90799f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-01-31  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/42898
+	* gcc.dg/torture/pr42898-2.c: New test.
+
 2010-01-31  Richard Guenther  <rguenther@suse.de>
 
 	* gcc.dg/torture/pr42898.c: Skip -O0.
diff --git a/gcc/testsuite/gcc.dg/torture/pr42898-2.c b/gcc/testsuite/gcc.dg/torture/pr42898-2.c
new file mode 100644
index 000000000000..32c94273b135
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr42898-2.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+/* { dg-options "-fdump-tree-optimized" } */
+
+struct hardware {
+  int parm1:8;
+  int :4;
+  int parm2:4;
+  int parm3:15;
+  int parm4:1;
+};
+
+const struct hardware h = {
+  .parm1=42,
+  .parm2=13,
+  .parm3=11850,
+  .parm4=1,
+};
+
+void f1(volatile struct hardware *ptr)
+{
+  *ptr = h;
+}
+
+/* { dg-final { scan-tree-dump-times "\\*ptr" 1 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */