diff mbox

[3/4,AArch64] Add CCMP to rtx costs

Message ID 000201d11e2c$b39f2240$1add66c0$@arm.com
State New
Headers show

Commit Message

Wilco Dijkstra Nov. 13, 2015, 4:02 p.m. UTC 
This patch adds support for rtx costing of CCMP. The cost is the same as
int/FP compare, however comparisons with zero get a slightly larger cost.
This means we prefer emitting compares with zero so they can be merged with
ALU operations.

OK for commit?

ChangeLog:
2015-11-13  Wilco Dijkstra  <wdijkstr@arm.com>

	* gcc/config/aarch64/aarch64.c (aarch64_if_then_else_costs):
	Add support for CCMP costing.

---
 gcc/config/aarch64/aarch64.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
diff mbox

Patch

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index a224982..b789841 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -5638,6 +5638,26 @@  aarch64_if_then_else_costs (rtx op0, rtx op1, rtx
op2, int *cost, bool speed)
     }
   else if (GET_MODE_CLASS (GET_MODE (inner)) == MODE_CC)
     {
+      /* CCMP.  */
+      if ((GET_CODE (op1) == COMPARE) && CONST_INT_P (op2))
+	{
+	  /* Increase cost of CCMP reg, 0, imm, CC to prefer CMP reg, 0.  */
+	  if (XEXP (op1, 1) == const0_rtx)
+	    *cost += 1;
+	  if (speed)
+	    {
+	      machine_mode mode = GET_MODE (XEXP (op1, 0));
+	      const struct cpu_cost_table *extra_cost
+		= aarch64_tune_params.insn_extra_cost;
+
+	      if (GET_MODE_CLASS (mode) == MODE_INT)
+		*cost += extra_cost->alu.arith;
+	      else
+		*cost += extra_cost->fp[mode == DFmode].compare;
+	    }
+	  return true;
+	}
+
       /* It's a conditional operation based on the status flags,
 	 so it must be some flavor of CSEL.  */