re PR tree-optimization/53168 (ICE in find_or_generate_expression, at tree-ssa-pre.c:3053)

2012-05-04  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53168
	* tree-ssa-pre.c (phi_translate_1): Only handle type-punned
	memory reads when the result is a constant we can pun.

	* gcc.dg/torture/pr53168.c: New testcase.
	* gcc.dg/tree-ssa/ssa-pre-30.c: Likewise.

From-SVN: r187153

5 files changed, 89 insertions, 56 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 63ec602..72e3264 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2012-05-04  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/53168
+	* tree-ssa-pre.c (phi_translate_1): Only handle type-punned
+	memory reads when the result is a constant we can pun.
+
+2012-05-04  Richard Guenther  <rguenther@suse.de>
+
 	* common.opt (flto-report): Do not mark as Optimization.
 
 2012-05-04  Eric Botcazou  <ebotcazou@adacore.com>
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 581b8b8..e26d072 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2012-05-04  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/53168
+	* gcc.dg/torture/pr53168.c: New testcase.
+	* gcc.dg/tree-ssa/ssa-pre-30.c: Likewise.
+
+2012-05-04  Richard Guenther  <rguenther@suse.de>
+
 	* gcc.dg/lto/pr53214_0.c: New testcase.
 
 2012-05-04  Eric Botcazou  <ebotcazou@adacore.com>
diff --git a/gcc/testsuite/gcc.dg/torture/pr53168.c b/gcc/testsuite/gcc.dg/torture/pr53168.c
new file mode 100644
index 0000000..0b9a8dc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr53168.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+
+int a, b, c;
+unsigned *d;
+int e[1];
+void fn1 ();
+int fn2 ();
+int
+fn3 ()
+{
+  int *f = &a;
+  if (fn2 ())
+    {
+      for (; c; c++)
+	{
+	  e[a] && (b = 0);
+	  fn1 ();
+	  if (e[a])
+	    return 0;
+	}
+      for (; c <= 0; c++)
+	for (;;)
+	  ;
+    }
+  else
+    e[0] = 0 != (d = f);
+  return *d;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-30.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-30.c
new file mode 100644
index 0000000..68a7a7f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-30.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-pre-details" } */
+
+int f;
+int g;
+unsigned int
+foo (int b, int x)
+{
+  if (b)
+    x = *(int *)&f;
+  g = x;
+  return *(unsigned int*)&f;
+}
+float
+bar (int b, int x)
+{
+  if (b)
+    x = *(int *)&f;
+  g = x;
+  return *(float *)&f;
+}
+
+/* We should see the partial redundant loads of f even though they
+   are using different types (of the same size).  */
+
+/* { dg-final { scan-tree-dump-times "Replaced MEM" 2 "pre" } } */
+/* { dg-final { cleanup-tree-dump "pre" } } */
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 776a37c..fcd7fee 100644
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -1659,7 +1659,6 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 	  {
 	    unsigned int new_val_id;
 	    pre_expr constant;
-	    bool converted = false;
 
 	    tree result = vn_reference_lookup_pieces (newvuse, ref->set,
 						      ref->type,
@@ -1668,12 +1667,29 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 	    if (result)
 	      VEC_free (vn_reference_op_s, heap, newoperands);
 
-	    if (result
-		&& !useless_type_conversion_p (ref->type, TREE_TYPE (result)))
+	    /* We can always insert constants, so if we have a partial
+	       redundant constant load of another type try to translate it
+	       to a constant of appropriate type.  */
+	    if (result && is_gimple_min_invariant (result))
 	      {
-		result = fold_build1 (VIEW_CONVERT_EXPR, ref->type, result);
-		converted = true;
+		tree tem = result;
+		if (!useless_type_conversion_p (ref->type, TREE_TYPE (result)))
+		  {
+		    tem = fold_unary (VIEW_CONVERT_EXPR, ref->type, result);
+		    if (tem && !is_gimple_min_invariant (tem))
+		      tem = NULL_TREE;
+		  }
+		if (tem)
+		  return get_or_alloc_expr_for_constant (tem);
 	      }
+
+	    /* If we'd have to convert things we would need to validate
+	       if we can insert the translated expression.  So fail
+	       here for now - we cannot insert an alias with a different
+	       type in the VN tables either, as that would assert.  */
+	    if (result
+		&& !useless_type_conversion_p (ref->type, TREE_TYPE (result)))
+	      return NULL;
 	    else if (!result && newref
 		     && !useless_type_conversion_p (ref->type, newref->type))
 	      {
@@ -1681,61 +1697,11 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
 		return NULL;
 	      }
 
-	    if (result && is_gimple_min_invariant (result))
-	      {
-	        gcc_assert (!newoperands);
-	        return get_or_alloc_expr_for_constant (result);
-	      }
-
 	    expr = (pre_expr) pool_alloc (pre_expr_pool);
 	    expr->kind = REFERENCE;
 	    expr->id = 0;
 
-	    if (converted)
-	      {
-		vn_nary_op_t nary;
-		tree nresult;
-
-		gcc_assert (CONVERT_EXPR_P (result)
-			    || TREE_CODE (result) == VIEW_CONVERT_EXPR);
-
-		nresult = vn_nary_op_lookup_pieces (1, TREE_CODE (result),
-						    TREE_TYPE (result),
-						    &TREE_OPERAND (result, 0),
-						    &nary);
-		if (nresult && is_gimple_min_invariant (nresult))
-		  return get_or_alloc_expr_for_constant (nresult);
-
-		expr->kind = NARY;
-		if (nary)
-		  {
-		    PRE_EXPR_NARY (expr) = nary;
-		    constant = fully_constant_expression (expr);
-		    if (constant != expr)
-		      return constant;
-
-		    new_val_id = nary->value_id;
-		    get_or_alloc_expression_id (expr);
-		  }
-		else
-		  {
-		    new_val_id = get_next_value_id ();
-		    VEC_safe_grow_cleared (bitmap_set_t, heap,
-					   value_expressions,
-					   get_max_value_id() + 1);
-		    nary = vn_nary_op_insert_pieces (1, TREE_CODE (result),
-						     TREE_TYPE (result),
-						     &TREE_OPERAND (result, 0),
-						     NULL_TREE,
-						     new_val_id);
-		    PRE_EXPR_NARY (expr) = nary;
-		    constant = fully_constant_expression (expr);
-		    if (constant != expr)
-		      return constant;
-		    get_or_alloc_expression_id (expr);
-		  }
-	      }
-	    else if (newref)
+	    if (newref)
 	      {
 		PRE_EXPR_REFERENCE (expr) = newref;
 		constant = fully_constant_expression (expr);