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[RFC:,3/6,v2] Remove if_info->branch_cost

Message ID 1466524231-17412-3-git-send-email-james.greenhalgh@arm.com
State New
Headers show

Commit Message

James Greenhalgh June 21, 2016, 3:50 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.

Bootstrapped as part of the patch series on aarch64 and x86-64.

OK?

Thanks,
James

---
2016-06-21  James Greenhalgh  <james.greenhalgh@arm.com>

	* ifcvt.c (noce_if_info): Remove branch_cost.
	(noce_try_store_flag_mask): Use max_seq_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 0b97114..f4ad037 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -811,9 +811,6 @@  struct noce_if_info
   unsigned int then_cost;
   unsigned int else_cost;
 
-  /* Estimated cost of the particular branch instruction.  */
-  unsigned int branch_cost;
-
   /* Maximum permissible cost for the unconditional sequence we should
      generate to replace this branch.  */
   unsigned int max_seq_cost;
@@ -1683,7 +1680,8 @@  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->max_seq_cost + insn_cost;
 	  new_cost = seq_cost (seq, speed_p);
 
 	  if (new_cost > old_cost)
@@ -2159,7 +2157,9 @@  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->max_seq_cost)
     return FALSE;
 
   /* Possibly rearrange operands to make things come out more natural.  */
@@ -3341,8 +3341,8 @@  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->max_seq_cost now guides the maximum number of set instructions in
    a basic block which is considered profitable to completely
    if-convert.  */
 
@@ -3353,7 +3353,8 @@  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->max_seq_cost / COSTS_N_INSNS (1), param);
 
   FOR_BB_INSNS (test_bb, insn)
     {
@@ -4070,8 +4071,6 @@  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.max_seq_cost
     = targetm.max_noce_ifcvt_seq_cost (optimize_bb_for_speed_p (test_bb),
 				       then_edge);