[PATCH] Remove fold_cond_expr_cond

[Richard Biener <rguenther at suse dot de>]

So I stumbled across fold_cond_expr_cond and traced it back to
pre-GIMPLE and pre-fold_XXX times.  It "folds" all conditions in
a function (but only if they fold to always true/false).  It
does this after CFG construction but before cfg-cleanup.  It
does that to allow cfg-cleanup to be less expensive - but that's
all no longer true as cfg-cleanup basically does the very same
"folding" as fold_cond_expr_cond.

Then we have the other caller from tree_function_versioning
which folds all copied stmts anyway.

And fold_stmt does sth similar (but doesn't throw away non-true/false
results).  It just restricts itself a bit too much, so I removed
the redundant check.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2015-07-23  Richard Biener  <rguenther@suse.de>

	* gimple-fold.c (fold_gimple_cond): Do not require folding
	results to pass valid_gimple_rhs_p.
	* tree-cfg.h (fold_cond_expr_cond): Remove.
	* tree-cfg.c (fold_cond_expr_cond): Likewise.
	(make_edges): Do not call it.
	* tree-inline.c (tree_function_versioning): Likewise.

Index: gcc/gimple-fold.c
===================================================================
--- gcc/gimple-fold.c	(revision 226091)
+++ gcc/gimple-fold.c	(working copy)
@@ -546,7 +546,7 @@ fold_gimple_cond (gcond *stmt)
   if (result)
     {
       STRIP_USELESS_TYPE_CONVERSION (result);
-      if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result))
+      if (is_gimple_condexpr (result))
         {
           gimple_cond_set_condition_from_tree (stmt, result);
           return true;
Index: gcc/tree-cfg.h
===================================================================
--- gcc/tree-cfg.h	(revision 226091)
+++ gcc/tree-cfg.h	(working copy)
@@ -31,7 +31,6 @@ extern void gt_pch_nx (edge_def *e, gt_p
 
 extern void init_empty_tree_cfg_for_function (struct function *);
 extern void init_empty_tree_cfg (void);
-extern void fold_cond_expr_cond (void);
 extern void start_recording_case_labels (void);
 extern void end_recording_case_labels (void);
 extern basic_block label_to_block_fn (struct function *, tree);
Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c	(revision 226091)
+++ gcc/tree-cfg.c	(working copy)
@@ -606,48 +606,6 @@ create_bb (void *h, void *e, basic_block
 				 Edge creation
 ---------------------------------------------------------------------------*/
 
-/* Fold COND_EXPR_COND of each COND_EXPR.  */
-
-void
-fold_cond_expr_cond (void)
-{
-  basic_block bb;
-
-  FOR_EACH_BB_FN (bb, cfun)
-    {
-      gimple stmt = last_stmt (bb);
-
-      if (stmt && gimple_code (stmt) == GIMPLE_COND)
-	{
-	  gcond *cond_stmt = as_a <gcond *> (stmt);
-	  location_t loc = gimple_location (stmt);
-	  tree cond;
-	  bool zerop, onep;
-
-	  fold_defer_overflow_warnings ();
-	  cond = fold_binary_loc (loc, gimple_cond_code (cond_stmt),
-				  boolean_type_node,
-				  gimple_cond_lhs (cond_stmt),
-				  gimple_cond_rhs (cond_stmt));
-	  if (cond)
-	    {
-	      zerop = integer_zerop (cond);
-	      onep = integer_onep (cond);
-	    }
-	  else
-	    zerop = onep = false;
-
-	  fold_undefer_overflow_warnings (zerop || onep,
-					  stmt,
-					  WARN_STRICT_OVERFLOW_CONDITIONAL);
-	  if (zerop)
-	    gimple_cond_make_false (cond_stmt);
-	  else if (onep)
-	    gimple_cond_make_true (cond_stmt);
-	}
-    }
-}
-
 /* If basic block BB has an abnormal edge to a basic block
    containing IFN_ABNORMAL_DISPATCHER internal call, return
    that the dispatcher's basic block, otherwise return NULL.  */
@@ -1000,9 +958,6 @@ make_edges (void)
   XDELETE (bb_to_omp_idx);
 
   free_omp_regions ();
-
-  /* Fold COND_EXPR_COND of each COND_EXPR.  */
-  fold_cond_expr_cond ();
 }
 
 /* Add SEQ after GSI.  Start new bb after GSI, and created further bbs as
Index: gcc/tree-inline.c
===================================================================
--- gcc/tree-inline.c	(revision 226091)
+++ gcc/tree-inline.c	(working copy)
@@ -5847,7 +5847,6 @@ tree_function_versioning (tree old_decl,
 
   fold_marked_statements (0, id.statements_to_fold);
   delete id.statements_to_fold;
-  fold_cond_expr_cond ();
   delete_unreachable_blocks_update_callgraph (&id);
   if (id.dst_node->definition)
     cgraph_edge::rebuild_references ();