re PR middle-end/58145 (volatileness of write is discarded, perhaps in "lim1" related to loop optimizations)

	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.dg/pr58145-1.c: New test.
	* gcc.dg/pr58145-2.c: New test.

From-SVN: r201748

5 files changed, 108 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5d846b1..c7f229b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,11 @@
+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.
+
 2013-08-14  Xinliang David Li  <davidxl@google.com>
+
 	* config/i386/i386.c (ix86_option_override_internal):
 	Fix potential unitialized variable error.
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c6f97fc..c56c260 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+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.
+
 2013-08-14  Joern Rennecke <joern.rennecke@embecosm.com>
 
 	* gcc.dg/debug/dwarf2/dwarf2.exp: Replace -gdwarf-2 with -gdwarf.
diff --git a/gcc/testsuite/gcc.dg/pr58145-1.c b/gcc/testsuite/gcc.dg/pr58145-1.c
new file mode 100644
index 0000000..0e236c0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr58145-1.c
@@ -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" } } */
diff --git a/gcc/testsuite/gcc.dg/pr58145-2.c b/gcc/testsuite/gcc.dg/pr58145-2.c
new file mode 100644
index 0000000..840e982
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr58145-2.c
@@ -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" } } */
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 2bce848..8e3bb81 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -1466,6 +1466,7 @@ build_ref_for_offset (location_t loc, tree base, HOST_WIDE_INT offset,
 {
   tree prev_base = base;
   tree off;
+  tree mem_ref;
   HOST_WIDE_INT base_offset;
   unsigned HOST_WIDE_INT misalign;
   unsigned int align;
@@ -1516,7 +1517,12 @@ build_ref_for_offset (location_t loc, tree base, HOST_WIDE_INT offset,
   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;
 }
 
 /* Construct a memory reference to a part of an aggregate BASE at the given