re PR tree-optimization/29964 (function with volatile operators still found to be pure)

2006-11-24  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR tree-opt/29964
        * ipa-pure-const.c (check_tree): If the original tree
        is volatile return early and say the function is not pure
        nor const.  Remove the volatile check for writes.
        (analyze_function): Print out the result of the local
        analysis pass.

2006-11-24  Andrew Pinski  <andrew_pinski@playstation.sony.com>

        PR tree-opt/29964
        * gcc.dg/pure-1.c: New test.

From-SVN: r119162

4 files changed, 53 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 85c0349..12c14de 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2006-11-24  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR tree-opt/29964
+	* ipa-pure-const.c (check_tree): If the original tree
+	is volatile return early and say the function is not pure
+	nor const.  Remove the volatile check for writes.  
+	(analyze_function): Print out the result of the local
+	analysis pass.
+
 2006-11-24  Joseph Myers  <joseph@codesourcery.com>
 
 	* config/rs6000/eabispe.h (TARGET_DEFAULT): Include
diff --git a/gcc/ipa-pure-const.c b/gcc/ipa-pure-const.c
index 041cf29..fdaff50 100644
--- a/gcc/ipa-pure-const.c
+++ b/gcc/ipa-pure-const.c
@@ -166,6 +166,14 @@ check_tree (funct_state local, tree t, bool checking_write)
   if ((TREE_CODE (t) == EXC_PTR_EXPR) || (TREE_CODE (t) == FILTER_EXPR))
     return;
 
+  /* Any tree which is volatile disqualifies thie function from being
+     const or pure. */
+  if (TREE_THIS_VOLATILE (t))
+    {
+      local->pure_const_state = IPA_NEITHER;
+      return;
+    }
+
   while (TREE_CODE (t) == REALPART_EXPR 
 	 || TREE_CODE (t) == IMAGPART_EXPR
 	 || handled_component_p (t))
@@ -183,12 +191,13 @@ check_tree (funct_state local, tree t, bool checking_write)
       
       /* Any indirect reference that occurs on the lhs
 	 disqualifies the function from being pure or const. Any
-	 indirect reference to a volatile disqualifies the
-	 function from being pure or const.  Any indirect
-	 reference that occurs on the rhs disqualifies the
+	 indirect reference that occurs on the rhs disqualifies the
 	 function from being const.  */
-      if (checking_write || TREE_THIS_VOLATILE (t)) 
-	local->pure_const_state = IPA_NEITHER;
+      if (checking_write) 
+	{
+	  local->pure_const_state = IPA_NEITHER;
+	  return;
+	}
       else if (local->pure_const_state == IPA_CONST)
 	local->pure_const_state = IPA_PURE;
     }
@@ -541,7 +550,7 @@ analyze_function (struct cgraph_node *fn)
 	      walk_tree (bsi_stmt_ptr (bsi), scan_function, 
 			 fn, visited_nodes);
 	      if (l->pure_const_state == IPA_NEITHER) 
-		return;
+		goto end;
 	    }
 	}
 
@@ -568,6 +577,14 @@ analyze_function (struct cgraph_node *fn)
 	  pop_cfun ();
 	}
     }
+
+end:
+  if (dump_file)
+    {
+      fprintf (dump_file, "after local analysis of %s with initial value = %d\n ", 
+	       cgraph_node_name (fn),
+	       l->pure_const_state);
+    }
 }
 
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 05fb4f6..49a333b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2006-11-24  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR tree-opt/29964
+	* gcc.dg/pure-1.c: New test.
+
 2006-11-24  Joseph Myers  <joseph@codesourcery.com>
 
 	* g++.dg/eh/simd-2.C: Use -O -w in general for PowerPC.
diff --git a/gcc/testsuite/gcc.dg/pure-1.c b/gcc/testsuite/gcc.dg/pure-1.c
new file mode 100644
index 0000000..f365c8d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pure-1.c
@@ -0,0 +1,16 @@
+/* Regression test for PR middle-end/23584 */
+/* Verify that dereferencing a volatile element in a struct causes
+   the function not be pure.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-ipa-pure-const" } */
+
+struct test_a { volatile int a; };
+
+int func_a(struct test_a *a)
+{
+        return a->a;
+}
+
+/* { dg-final { scan-ipa-dump-not "found to be pure: func_a" "pure-const" } } */
+/* { dg-final { cleanup-ipa-dump "pure-const" } } */