[backport gcc-4.8.2 r201749 <mikpe@it.uu.se>]

gcc/

2013-08-14  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/58145
	* tree-sra.c (build_ref_for_offset): If prev_base has
	TREE_THIS_VOLATILE or TREE_SIDE_EFFECTS, propagate it to MEM_REF.

gcc/testsuite/

2013-08-14  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/58145
	* gcc.dg/pr58145-1.c: New test.
	* gcc.dg/pr58145-2.c: New test.

--- gcc-4.7.3/gcc/testsuite/gcc.dg/pr58145-1.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.7.3/gcc/testsuite/gcc.dg/pr58145-1.c	2013-08-17 11:28:28.395810011 +0200
@@ -0,0 +1,37 @@
+/* PR tree-optimization/58145 */
+/* { dg-do compile { target { int32plus } } } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+struct S { unsigned int data : 32; };
+struct T { unsigned int data; };
+volatile struct S s2;
+
+void
+f1 (int val)
+{
+  struct S s = { .data = val };
+  *(volatile struct S *) 0x880000UL = s;
+}
+
+void
+f2 (int val)
+{
+  struct T t = { .data = val };
+  *(volatile struct T *) 0x880000UL = t;
+}
+
+void
+f3 (int val)
+{
+  *(volatile unsigned int *) 0x880000UL = val;
+}
+
+void
+f4 (int val)
+{
+  struct S s = { .data = val };
+  s2 = s;
+}
+
+/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
--- gcc-4.7.3/gcc/testsuite/gcc.dg/pr58145-2.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.7.3/gcc/testsuite/gcc.dg/pr58145-2.c	2013-08-17 11:28:28.395810011 +0200
@@ -0,0 +1,51 @@
+/* PR tree-optimization/58145 */
+/* { dg-do compile { target { int32plus } } } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+struct S { unsigned int data : 32; };
+struct T { unsigned int data; };
+volatile struct S s2;
+
+static inline void
+f1 (int val)
+{
+  struct S s = { .data = val };
+  *(volatile struct S *) 0x880000UL = s;
+}
+
+static inline void
+f2 (int val)
+{
+  struct T t = { .data = val };
+  *(volatile struct T *) 0x880000UL = t;
+}
+
+static inline void
+f3 (int val)
+{
+  *(volatile unsigned int *) 0x880000UL = val;
+}
+
+static inline void
+f4 (int val)
+{
+  struct S s = { .data = val };
+  s2 = s;
+}
+
+void
+f5 (void)
+{
+  int i;
+  for (i = 0; i < 100; i++)
+    f1 (0);
+  for (i = 0; i < 100; i++)
+    f2 (0);
+  for (i = 0; i < 100; i++)
+    f3 (0);
+  for (i = 0; i < 100; i++)
+    f4 (0);
+}
+
+/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
--- gcc-4.7.3/gcc/tree-sra.c.~1~	2013-01-24 15:53:56.000000000 +0100
+++ gcc-4.7.3/gcc/tree-sra.c	2013-08-17 11:28:28.395810011 +0200
@@ -1480,6 +1480,7 @@ build_ref_for_offset (location_t loc, tr
 {
   tree prev_base = base;
   tree off;
+  tree mem_ref;
   HOST_WIDE_INT base_offset;
   unsigned HOST_WIDE_INT misalign;
   unsigned int align;
@@ -1547,7 +1548,12 @@ build_ref_for_offset (location_t loc, tr
   if (align < TYPE_ALIGN (exp_type))
     exp_type = build_aligned_type (exp_type, align);
 
-  return fold_build2_loc (loc, MEM_REF, exp_type, base, off);
+  mem_ref = fold_build2_loc (loc, MEM_REF, exp_type, base, off);
+  if (TREE_THIS_VOLATILE (prev_base))
+    TREE_THIS_VOLATILE (mem_ref) = 1;
+  if (TREE_SIDE_EFFECTS (prev_base))
+    TREE_SIDE_EFFECTS (mem_ref) = 1;
+  return mem_ref;
 }
 
 DEF_VEC_ALLOC_P_STACK (tree);