PR tree-optimization/20933

	* tree-ssa-alias.c (compute_flow_insensitive_aliasing): Move
	logic to reject aliases between read-only and writable
	variables ...
	(may_alias_p): ... here.
	(get_tmt_for): Do not associate read-only tags to pointers
	whose pointed-to type is not read-only.
	* tree-ssa.c (verify_ssa): Check that memory stores have at
	least one V_MAY_DEF or V_MUST_DEF.

testsuite/ChangeLog

	PR tree-optimization/20933
	* gcc.dg/tree-ssa/pr20933.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@97988 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0c7d095..6d4dd6a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2005-04-11  Diego Novillo  <dnovillo@redhat.com>
+
+       PR tree-optimization/20933
+       * tree-ssa-alias.c (compute_flow_insensitive_aliasing): Move
+       logic to reject aliases between read-only and writable
+       variables ...
+       (may_alias_p): ... here.
+       (get_tmt_for): Do not associate read-only tags to pointers
+       whose pointed-to type is not read-only.
+       * tree-ssa.c (verify_ssa): Check that memory stores have at
+       least one V_MAY_DEF or V_MUST_DEF.
+
 2005-04-11  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
        PR/17092

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2b10695..5271167 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2005-04-11  Diego Novillo  <dnovillo@redhat.com>
+
+       PR tree-optimization/20933
+       * gcc.dg/tree-ssa/pr20933.c: New test.
+
 2005-04-11  Tobias Schl"uter  <tobias.schlueter@physik.uni-muenchen.de>
 
        * gfortran.dg/fold_nearest.f90: New test.

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr20933.c b/gcc/testsuite/gcc.dg/tree-ssa/pr20933.c
new file mode 100644 (file)
index 0000000..d32d600
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr20933.c
@@ -0,0 +1,70 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern __SIZE_TYPE__ strlen (__const char *__s)
+     __attribute__ ((__nothrow__)) __attribute__ ((__pure__)) __attribute__ ((__nonnull__ (1)));
+extern char *strcpy (char *__restrict __dest, __const char *__restrict __src)
+     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1, 2)));
+extern char *getenv (__const char *__name) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
+extern int access (__const char *__name, int __type) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
+extern void * xmalloc (__SIZE_TYPE__) __attribute__ ((__malloc__));
+
+static __inline__ const char *
+try (const char *dir, const char *base)
+{
+  if (base != 0)
+    return base;
+  if (dir != 0
+      && access (dir, 4 | 2 | 1) == 0)
+    return dir;
+  return 0;
+}
+
+static const char tmp[] = { '/', 't', 'm', 'p', 0 };
+static const char usrtmp[] =
+{ '/', 'u', 's', 'r', '/', 't', 'm', 'p', 0 };
+static const char vartmp[] =
+{ '/', 'v', 'a', 'r', '/', 't', 'm', 'p', 0 };
+
+static char *memoized_tmpdir;
+char *
+choose_tmpdir (void)
+{
+  const char *base = 0;
+  char *tmpdir;
+  unsigned int len;
+
+  if (memoized_tmpdir)
+    return memoized_tmpdir;
+
+  base = try (getenv ("TMPDIR"), base);
+  base = try (getenv ("TMP"), base);
+  base = try (getenv ("TEMP"), base);
+
+
+  base = try ("/tmp", base);
+
+
+
+  base = try (vartmp, base);
+  base = try (usrtmp, base);
+  base = try (tmp, base);
+
+
+  if (base == 0)
+    base = ".";
+
+
+
+  len = strlen (base);
+  tmpdir = xmalloc (len + 2);
+  strcpy (tmpdir, base);
+  /* Alias analysis was associating read-only memory tags to pointers
+     that are not read-only.  We would then not issue any V_MAY_DEF in
+     this store.  */
+  tmpdir[len] = '/';
+  tmpdir[len+1] = '\0';
+
+  memoized_tmpdir = tmpdir;
+  return tmpdir;
+}

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 7d8e783..c0bce92 100644 (file)
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -1001,10 +1001,6 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
          if (!tag_stored_p && !var_stored_p)
            continue;
 
-         if ((unmodifiable_var_p (tag) && !unmodifiable_var_p (var))
-             || (unmodifiable_var_p (var) && !unmodifiable_var_p (tag)))
-           continue;
-
          if (may_alias_p (p_map->var, p_map->set, var, v_map->set))
            {
              subvar_t svars;
@@ -1719,6 +1715,16 @@ may_alias_p (tree ptr, HOST_WIDE_INT mem_alias_set,
       return false;
     }
 
+  /* If either MEM or VAR is a read-only global and the other one
+     isn't, then PTR cannot point to VAR.  */
+  if ((unmodifiable_var_p (mem) && !unmodifiable_var_p (var))
+      || (unmodifiable_var_p (var) && !unmodifiable_var_p (mem)))
+    {
+      alias_stats.alias_noalias++;
+      alias_stats.simple_resolved++;
+      return false;
+    }
+
   m_ann = var_ann (mem);
 
   gcc_assert (m_ann->mem_tag_kind == TYPE_TAG);
@@ -2319,9 +2325,11 @@ get_tmt_for (tree ptr, struct alias_info *ai)
   for (i = 0, tag = NULL_TREE; i < ai->num_pointers; i++)
     {
       struct alias_map_d *curr = ai->pointers[i];
-      if (tag_set == curr->set)
+      tree curr_tag = var_ann (curr->var)->type_mem_tag;
+      if (tag_set == curr->set
+         && TYPE_READONLY (tag_type) == TYPE_READONLY (TREE_TYPE (curr_tag)))
        {
-         tag = var_ann (curr->var)->type_mem_tag;
+         tag = curr_tag;
          break;
        }
     }
@@ -2356,6 +2364,10 @@ get_tmt_for (tree ptr, struct alias_info *ai)
      pointed-to type.  */
   gcc_assert (tag_set == get_alias_set (tag));
 
+  /* If PTR's pointed-to type is read-only, then TAG's type must also
+     be read-only.  */
+  gcc_assert (TYPE_READONLY (tag_type) == TYPE_READONLY (TREE_TYPE (tag)));
+
   return tag;
 }
 

diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c
index c152f82..1e232e3 100644 (file)
--- a/gcc/tree-ssa.c
+++ b/gcc/tree-ssa.c
@@ -707,16 +707,37 @@ verify_ssa (bool check_modified_stmt)
              goto err;
            }
 
+         if (TREE_CODE (stmt) == MODIFY_EXPR
+             && TREE_CODE (TREE_OPERAND (stmt, 0)) != SSA_NAME)
+           {
+             tree lhs, base_address;
+
+             lhs = TREE_OPERAND (stmt, 0);
+             base_address = get_base_address (lhs);
 
-             if (stmt_ann (stmt)->makes_aliased_stores 
-                 && NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt)) == 0)
+             if (base_address
+                 && SSA_VAR_P (base_address)
+                 && NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt)) == 0
+                 && NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt)) == 0)
                {
-                 error ("Statement makes aliased stores, but has no V_MAY_DEFS");
+                 error ("Statement makes a memory store, but has no "
+                        "V_MAY_DEFS nor V_MUST_DEFS");
                  print_generic_stmt (stderr, stmt, TDF_VOPS);
                  goto err;
                }
+           }
+
+
+         if (stmt_ann (stmt)->makes_aliased_stores 
+             && NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt)) == 0)
+           {
+             error ("Statement makes aliased stores, but has no V_MAY_DEFS");
+             print_generic_stmt (stderr, stmt, TDF_VOPS);
+             goto err;
+           }
 
-         FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES | SSA_OP_ALL_KILLS)
+         FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter,
+                                   SSA_OP_ALL_USES | SSA_OP_ALL_KILLS)
            {
              op = USE_FROM_PTR (use_p);
              if (verify_use (bb, definition_block[SSA_NAME_VERSION (op)],