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[RFC:,3/6] Remove if_info->branch_cost

Message ID 1464886438-17892-4-git-send-email-james.greenhalgh@arm.com
State Superseded
Headers show

Commit Message

James Greenhalgh June 2, 2016, 4:53 p.m. UTC 
Hi,

This patch removes what is left of branch_cost uses, moving them to use
the new hook and tagging each left over spot with a TODO to revisit them.
All these uses are in rtx costs units, so we don't have more work to do at
this point.

OK?

Thanks,
James

---
2016-06-02  James Greenhalgh  <james.greenhalgh@arm.com>

	* ifcvt.c (noce_if_info): Remove branch_cost.
	(noce_try_store_flag_mask): Use rtx_edge_cost rather than
	branch_cost, tag as a TODO..
	(noce_try_cmove_arith): Likewise.
	(noce_convert_multiple_sets): Likewise.
	(bb_ok_for_noce_convert_multiple_sets): Likewise.
	(noce_find_if_block): Remove set of branch_cost.
diff mbox

Patch

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index 22cb5e7..b192c85 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -812,7 +812,6 @@  struct noce_if_info
   unsigned int else_cost;
 
   /* Estimated cost of the particular branch instruction.  */
-  unsigned int branch_cost;
   unsigned int rtx_edge_cost;
 };
 
@@ -1634,7 +1633,8 @@  noce_try_store_flag_mask (struct noce_if_info *if_info)
 
 	  speed_p = optimize_bb_for_speed_p (BLOCK_FOR_INSN (if_info->insn_a));
 	  insn_cost = insn_rtx_cost (PATTERN (if_info->insn_a), speed_p);
-	  old_cost = COSTS_N_INSNS (if_info->branch_cost) + insn_cost;
+	  /* TODO: Revisit this cost model.  */
+	  old_cost = if_info->rtx_edge_cost + insn_cost;
 	  new_cost = seq_cost (seq, speed_p);
 
 	  if (new_cost > old_cost)
@@ -2105,7 +2105,9 @@  noce_try_cmove_arith (struct noce_if_info *if_info)
 
   /* We're going to execute one of the basic blocks anyway, so
      bail out if the most expensive of the two blocks is unacceptable.  */
-  if (MAX (then_cost, else_cost) > COSTS_N_INSNS (if_info->branch_cost))
+
+  /* TODO: Revisit cost model.  */
+  if (MAX (then_cost, else_cost) > if_info->rtx_edge_cost)
     return FALSE;
 
   /* Possibly rearrange operands to make things come out more natural.  */
@@ -3280,8 +3282,8 @@  noce_convert_multiple_sets (struct noce_if_info *if_info)
    of conditional moves.  FORNOW: Use II to find the expected cost of
    the branch into/over TEST_BB.
 
-   TODO: This creates an implicit "magic number" for branch_cost.
-   II->branch_cost now guides the maximum number of set instructions in
+   TODO: This creates an implicit "magic number" for if conversion.
+   II->rtx_edge_cost now guides the maximum number of set instructions in
    a basic block which is considered profitable to completely
    if-convert.  */
 
@@ -3292,7 +3294,8 @@  bb_ok_for_noce_convert_multiple_sets (basic_block test_bb,
   rtx_insn *insn;
   unsigned count = 0;
   unsigned param = PARAM_VALUE (PARAM_MAX_RTL_IF_CONVERSION_INSNS);
-  unsigned limit = MIN (ii->branch_cost, param);
+  /* TODO:  Revisit this cost model.  */
+  unsigned limit = MIN (ii->rtx_edge_cost / COSTS_N_INSNS (1), param);
 
   FOR_BB_INSNS (test_bb, insn)
     {
@@ -3993,8 +3996,6 @@  noce_find_if_block (basic_block test_bb, edge then_edge, edge else_edge,
   if_info.cond_earliest = cond_earliest;
   if_info.jump = jump;
   if_info.then_else_reversed = then_else_reversed;
-  if_info.branch_cost = BRANCH_COST (optimize_bb_for_speed_p (test_bb),
-				     predictable_edge_p (then_edge));
   if_info.rtx_edge_cost
     = targetm.rtx_branch_cost (optimize_bb_for_speed_p (test_bb),
 			       predictable_edge_p (then_edge));