Implement new immediate use iterators.

2006-04-27  Andrew MacLeod  <amacleod@redhat.com>

	PR tree-optimization/26854
	* tree-vrp.c (remove_range_assertions): Use new Immuse iterator.
	* doc/tree-ssa.texi: Update immuse iterator documentation.
	* tree-ssa-math-opts.c (execute_cse_reciprocals_1): Use new iterator.
	* tree-ssa-dom.c (propagate_rhs_into_lhs): Use new iterator.
	* tree-flow-inline.h (end_safe_imm_use_traverse, end_safe_imm_use_p,
	first_safe_imm_use, next_safe_imm_use): Remove.
	(end_imm_use_stmt_p): New.  Check for end of immuse stmt traversal.
	(end_imm_use_stmt_traverse): New.  Terminate immuse stmt traversal.
	(move_use_after_head): New.  Helper function to sort immuses in a stmt.
	(link_use_stmts_after): New.  Link all immuses in a stmt consescutively.
	(first_imm_use_stmt): New.  Get first stmt in an immuse list.
	(next_imm_use_stmt): New.  Get next stmt in an immuse list.
	(first_imm_use_on_stmt): New.  Get first immuse on a stmt.
	(end_imm_use_on_stmt_p): New.  Check for end of immuses on a stmt.
	(next_imm_use_on_stmt): New.  Move to next immuse on a stmt.
	* tree-ssa-forwprop.c (forward_propagate_addr_expr): Use new iterator.
	* lambda-code.c (lambda_loopnest_to_gcc_loopnest): Use new iterator.
	(perfect_nestify): Use new iterator.
	* tree-vect-transform.c (vect_create_epilog_for_reduction): Use new 
	iterator.
	* tree-flow.h (struct immediate_use_iterator_d): Add comments.
	(next_imm_name): New field in struct immediate_use_iterator_d.
	(FOR_EACH_IMM_USE_SAFE, BREAK_FROM_SAFE_IMM_USE): Remove.
	(FOR_EACH_IMM_USE_STMT, BREAK_FROM_IMM_USE_STMT, 
	FOR_EACH_IMM_USE_ON_STMT): New immediate use iterator macros.
	* tree-cfg.c (replace_uses_by): Use new iterator.
	* tree-ssa-threadedge.c (lhs_of_dominating_assert): Use new iterator.
	* tree-ssa-operands.c (correct_use_link): Remove.
	(finalize_ssa_use_ops): No longer call correct_use_link.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@113321 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 6 insertions, 21 deletions

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index 2777d550916..431f8564bd3 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -2118,6 +2118,7 @@ propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
     {
       use_operand_p use_p;
       imm_use_iterator iter;
+      tree use_stmt;
       bool all = true;
 
       /* Dump details.  */
@@ -2134,10 +2135,8 @@ propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
       /* Walk over every use of LHS and try to replace the use with RHS. 
 	 At this point the only reason why such a propagation would not
 	 be successful would be if the use occurs in an ASM_EXPR.  */
-    repeat:
-      FOR_EACH_IMM_USE_SAFE (use_p, iter, lhs)
+      FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
 	{
-	  tree use_stmt = USE_STMT (use_p);
 	
 	  /* It's not always safe to propagate into an ASM_EXPR.  */
 	  if (TREE_CODE (use_stmt) == ASM_EXPR
@@ -2156,7 +2155,8 @@ propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
 	    }
 
 	  /* Propagate the RHS into this use of the LHS.  */
-	  propagate_value (use_p, rhs);
+	  FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+	    propagate_value (use_p, rhs);
 
 	  /* Special cases to avoid useless calls into the folding
 	     routines, operand scanning, etc.
@@ -2303,23 +2303,8 @@ propagate_rhs_into_lhs (tree stmt, tree lhs, tree rhs, bitmap interesting_names)
 	    }
 	}
 
-      /* Due to a bug in the immediate use iterator code, we can
-	 miss visiting uses in some cases when there is more than
-	 one use in a statement.  Missing a use can cause a multitude
-         of problems if we expected to eliminate all uses and remove
-         the defining statement.
-
-	 Until Andrew can fix the iterator, this hack will detect
-	 the cases which cause us problems.  Namely if ALL is set
-	 and we still have some immediate uses, then we must have
-	 skipped one or more in the loop above.  So just re-execute
-	 the loop.
-
-	 The maximum number of times we can re-execute the loop is
-	 bounded by the maximum number of times a given SSA_NAME
-	 appears in a single statement.  */
-      if (all && !has_zero_uses (lhs))
-	goto repeat;
+      /* Ensure there is nothing else to do. */ 
+      gcc_assert (all && has_zero_uses (lhs));
 
       /* If we were able to propagate away all uses of LHS, then
 	 we can remove STMT.  */