re PR tree-optimization/59025 (Revision 203979 causes failure in CPU2006 benchmark...

	PR tree-optimization/59025
	PR middle-end/60418
	* tree-ssa-reassoc.c (sort_by_operand_rank): For SSA_NAMEs with the
	same rank, sort by bb_rank and gimple_uid of SSA_NAME_DEF_STMT first.

From-SVN: r208535

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b88ee28f9c6af245d459eec446d8b5062ae16018..1982a7b7853a162124852a66c8ec06d90c86af78 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2014-03-13  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/59025
+       PR middle-end/60418
+       * tree-ssa-reassoc.c (sort_by_operand_rank): For SSA_NAMEs with the
+       same rank, sort by bb_rank and gimple_uid of SSA_NAME_DEF_STMT first.
+
 2014-03-13  Georg-Johann Lay  <avr@gjlay.de>
 
        PR target/60486

diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index 99282227039846ab14f84a1f75d33380d8b2bf6d..e9e29e550f7c0553f3f47ec60d66d98f27feff56 100644 (file)
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -219,6 +219,7 @@ static struct pointer_map_t *operand_rank;
 
 /* Forward decls.  */
 static long get_rank (tree);
+static bool reassoc_stmt_dominates_stmt_p (gimple, gimple);
 
 
 /* Bias amount for loop-carried phis.  We want this to be larger than
@@ -506,11 +507,37 @@ sort_by_operand_rank (const void *pa, const void *pb)
     }
 
   /* Lastly, make sure the versions that are the same go next to each
-     other.  We use SSA_NAME_VERSION because it's stable.  */
+     other.  */
   if ((oeb->rank - oea->rank == 0)
       && TREE_CODE (oea->op) == SSA_NAME
       && TREE_CODE (oeb->op) == SSA_NAME)
     {
+      /* As SSA_NAME_VERSION is assigned pretty randomly, because we reuse
+        versions of removed SSA_NAMEs, so if possible, prefer to sort
+        based on basic block and gimple_uid of the SSA_NAME_DEF_STMT.
+        See PR60418.  */
+      if (!SSA_NAME_IS_DEFAULT_DEF (oea->op)
+         && !SSA_NAME_IS_DEFAULT_DEF (oeb->op)
+         && SSA_NAME_VERSION (oeb->op) != SSA_NAME_VERSION (oea->op))
+       {
+         gimple stmta = SSA_NAME_DEF_STMT (oea->op);
+         gimple stmtb = SSA_NAME_DEF_STMT (oeb->op);
+         basic_block bba = gimple_bb (stmta);
+         basic_block bbb = gimple_bb (stmtb);
+         if (bbb != bba)
+           {
+             if (bb_rank[bbb->index] != bb_rank[bba->index])
+               return bb_rank[bbb->index] - bb_rank[bba->index];
+           }
+         else
+           {
+             bool da = reassoc_stmt_dominates_stmt_p (stmta, stmtb);
+             bool db = reassoc_stmt_dominates_stmt_p (stmtb, stmta);
+             if (da != db)
+               return da ? 1 : -1;
+           }
+       }
+
       if (SSA_NAME_VERSION (oeb->op) != SSA_NAME_VERSION (oea->op))
        return SSA_NAME_VERSION (oeb->op) - SSA_NAME_VERSION (oea->op);
       else