2011-02-07 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/47621
	* tree-ssa.c (non_rewritable_lvalue_p): New function, split out from
	two duplicates ...
	(execute_update_addresses_taken): ... here.  Make it more
	conservative in what we accept.

	* gcc.dg/torture/pr47621.c: New testcase.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@169881 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2c86129..cc625d9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2011-02-07  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/47621
+       * tree-ssa.c (non_rewritable_lvalue_p): New function, split out from
+       two duplicates ...
+       (execute_update_addresses_taken): ... here.  Make it more
+       conservative in what we accept.
+
 2011-02-06  Joseph Myers  <joseph@codesourcery.com>
 
        * config/sparc/freebsd.h (ASM_SPEC): Define.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fe9a2f7..558f192 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-02-07  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/47621
+       * gcc.dg/torture/pr47621.c: New testcase.
+
 2011-02-07  Uros Bizjak  <ubizjak@gmail.com>
 
        * gfortran.dg/transpose_optimization_2.f90: Cleanup original dump.

diff --git a/gcc/testsuite/gcc.dg/torture/pr47621.c b/gcc/testsuite/gcc.dg/torture/pr47621.c
new file mode 100644 (file)
index 0000000..882e67f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr47621.c
@@ -0,0 +1,14 @@
+/* { dg-do run } */
+
+extern void abort (void);
+
+int
+main (void)
+{
+  int data = 1;
+  struct ptr { int val; } *ptr = (struct ptr *) &data;
+  ptr->val = 0;
+  if (data != 0)
+    abort ();
+  return 0;
+}

diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c
index 7bd01f8..90fb5dd 100644 (file)
--- a/gcc/tree-ssa.c
+++ b/gcc/tree-ssa.c
@@ -1885,6 +1885,34 @@ non_rewritable_mem_ref_base (tree ref)
   return NULL_TREE;
 }
 
+/* For an lvalue tree LHS return true if it cannot be rewritten into SSA form.
+   Otherwise return true.  */
+
+static bool 
+non_rewritable_lvalue_p (tree lhs)
+{
+  /* A plain decl is always rewritable.  */
+  if (DECL_P (lhs))
+    return false;
+
+  /* A decl that is wrapped inside a MEM-REF that covers
+     it full is also rewritable.
+     ???  The following could be relaxed allowing component
+     references that do not change the access size.  */ ;
+  if (TREE_CODE (lhs) == MEM_REF
+      && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR
+      && integer_zerop (TREE_OPERAND (lhs, 1)))
+    {
+      tree decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0);
+      if (DECL_P (decl)
+         && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (lhs))
+         && (TREE_THIS_VOLATILE (decl) == TREE_THIS_VOLATILE (lhs)))
+       return false;
+    }
+
+  return true;
+}
+
 /* When possible, clear TREE_ADDRESSABLE bit or set DECL_GIMPLE_REG_P bit and
    mark the variable VAR for conversion into SSA.  Return true when updating
    stmts is required.  */
@@ -1978,29 +2006,13 @@ execute_update_addresses_taken (void)
          if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
            {
               tree lhs = gimple_get_lhs (stmt);
-
-              /* A plain decl does not need it set.  */
-              if (lhs && !DECL_P (lhs))
+              if (lhs
+                 && TREE_CODE (lhs) != SSA_NAME
+                 && non_rewritable_lvalue_p (lhs))
                {
-                 tree orig_lhs = lhs;
-
-                 while (handled_component_p (lhs))
-                   lhs = TREE_OPERAND (lhs, 0);
-
-                  if (DECL_P (lhs))
-                    bitmap_set_bit (not_reg_needs, DECL_UID (lhs));
-                 else if (TREE_CODE (lhs) == MEM_REF
-                          && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR)
-                   {
-                     decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0);
-                     if (DECL_P (decl)
-                         && (!integer_zerop (TREE_OPERAND (lhs, 1))
-                             || (DECL_SIZE (decl)
-                                 != TYPE_SIZE (TREE_TYPE (orig_lhs)))
-                             || (TREE_THIS_VOLATILE (lhs)
-                                 != TREE_THIS_VOLATILE (decl))))
-                       bitmap_set_bit (not_reg_needs, DECL_UID (decl));
-                   }
+                 decl = get_base_address (lhs);
+                 if (DECL_P (decl))
+                   bitmap_set_bit (not_reg_needs, DECL_UID (decl));
                 }
            }
 
@@ -2027,29 +2039,12 @@ execute_update_addresses_taken (void)
                {
                  tree link = gimple_asm_output_op (stmt, i);
                  tree lhs = TREE_VALUE (link);
-
-                 /* A plain decl does not need it set.  */
-                 if (!DECL_P (lhs))
+                 if (TREE_CODE (lhs) != SSA_NAME
+                     && non_rewritable_lvalue_p (lhs))
                    {
-                     tree orig_lhs = lhs;
-
-                     while (handled_component_p (lhs))
-                       lhs = TREE_OPERAND (lhs, 0);
-                 
-                     if (DECL_P (lhs))
-                       bitmap_set_bit (not_reg_needs, DECL_UID (lhs));
-                     else if (TREE_CODE (lhs) == MEM_REF
-                              && TREE_CODE (TREE_OPERAND (lhs, 0)) == ADDR_EXPR)
-                       {
-                         decl = TREE_OPERAND (TREE_OPERAND (lhs, 0), 0);
-                         if (DECL_P (decl)
-                             && (!integer_zerop (TREE_OPERAND (lhs, 1))
-                                 || (TYPE_MAIN_VARIANT (TREE_TYPE (decl))
-                                     != TYPE_MAIN_VARIANT (TREE_TYPE (orig_lhs)))
-                                 || (TREE_THIS_VOLATILE (lhs)
-                                     != TREE_THIS_VOLATILE (decl))))
-                           bitmap_set_bit (not_reg_needs, DECL_UID (decl));
-                       }
+                     decl = get_base_address (lhs);
+                     if (DECL_P (decl))
+                       bitmap_set_bit (not_reg_needs, DECL_UID (decl));
                    }
                }
              for (i = 0; i < gimple_asm_ninputs (stmt); ++i)