Patchwork Fix PR53774

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Submitter Richard Guenther
Date June 27, 2012, 11:25 a.m.
Message ID <alpine.LNX.2.00.1206271324260.15781@jbgna.fhfr.qr>
Download mbox | patch
Permalink /patch/167625/
State New
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Richard Guenther - June 27, 2012, 11:25 a.m.
This fixes PR53774, a case where reassoc produced non-canonical
statements like a = 4 + b.  The reason it did so was that it
assigned a rank of zero to things that are not constant.  Fixed
by pre-computing a rank for all SSA default defs.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2012-06-27  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53774
	* tree-ssa-reassoc.c (get_rank): All default defs have
	precomputed rank.
	(init_reassoc): Precompute rank for all SSA default defs.

Patch

Index: gcc/tree-ssa-reassoc.c
===================================================================
--- gcc/tree-ssa-reassoc.c	(revision 188987)
+++ gcc/tree-ssa-reassoc.c	(working copy)
@@ -383,14 +383,10 @@  get_rank (tree e)
       int i, n;
       tree op;
 
-      if (TREE_CODE (SSA_NAME_VAR (e)) == PARM_DECL
-	  && SSA_NAME_IS_DEFAULT_DEF (e))
+      if (SSA_NAME_IS_DEFAULT_DEF (e))
 	return find_operand_rank (e);
 
       stmt = SSA_NAME_DEF_STMT (e);
-      if (gimple_bb (stmt) == NULL)
-	return 0;
-
       if (gimple_code (stmt) == GIMPLE_PHI)
 	return phi_rank (stmt);
 
@@ -484,7 +480,7 @@  sort_by_operand_rank (const void *pa, co
   /* It's nicer for optimize_expression if constants that are likely
      to fold when added/multiplied//whatever are put next to each
      other.  Since all constants have rank 0, order them by type.  */
-  if (oeb->rank == 0 &&  oea->rank == 0)
+  if (oeb->rank == 0 && oea->rank == 0)
     {
       if (constant_type (oeb->op) != constant_type (oea->op))
 	return constant_type (oeb->op) - constant_type (oea->op);
@@ -3441,7 +3437,7 @@  transform_stmt_to_multiply (gimple_stmt_
       print_gimple_stmt (dump_file, stmt, 0, 0);
     }
 
-  gimple_assign_set_rhs_with_ops_1 (gsi, MULT_EXPR, rhs1, rhs2, NULL_TREE);
+  gimple_assign_set_rhs_with_ops (gsi, MULT_EXPR, rhs1, rhs2);
   update_stmt (gsi_stmt (*gsi));
   remove_visited_stmt_chain (rhs1);
 
@@ -3647,7 +3643,6 @@  init_reassoc (void)
 {
   int i;
   long rank = 2;
-  tree param;
   int *bbs = XNEWVEC (int, last_basic_block + 1);
 
   /* Find the loops, so that we can prevent moving calculations in
@@ -3666,24 +3661,15 @@  init_reassoc (void)
   bb_rank = XCNEWVEC (long, last_basic_block + 1);
   operand_rank = pointer_map_create ();
 
-  /* Give each argument a distinct rank.   */
-  for (param = DECL_ARGUMENTS (current_function_decl);
-       param;
-       param = DECL_CHAIN (param))
-    {
-      if (gimple_default_def (cfun, param) != NULL)
-	{
-	  tree def = gimple_default_def (cfun, param);
-	  insert_operand_rank (def, ++rank);
-	}
-    }
-
-  /* Give the chain decl a distinct rank. */
-  if (cfun->static_chain_decl != NULL)
-    {
-      tree def = gimple_default_def (cfun, cfun->static_chain_decl);
-      if (def != NULL)
-	insert_operand_rank (def, ++rank);
+  /* Give each default definition a distinct rank.  This includes
+     parameters and the static chain.  Walk backwards over all
+     SSA names so that we get proper rank ordering according
+     to tree_swap_operands_p.  */
+  for (i = num_ssa_names - 1; i > 0; --i)
+    {
+      tree name = ssa_name (i);
+      if (name && SSA_NAME_IS_DEFAULT_DEF (name))
+	insert_operand_rank (name, ++rank);
     }
 
   /* Set up rank for each BB  */