[AArch64 costs 8/18] Cost memory accesses using address costs

[James Greenhalgh]

Hi,

When we cost an RTX which touches memory, we really want to cost two
things. The cost of the memory operation, plus some additional cost
if we are using an expensive addressing mode.

This patch adds that modelling.

Tested in series on aarch64-none-elf.

OK for stage 1?

Thanks,
James

---
2014-03-27  James Greenhalgh  <james.greenha...@arm.com>
            Philipp Tomsich  <philipp.toms...@theobroma-systems.com>

        * config/aarch64/aarch64.c (aarch64_rtx_costs): Use address
        costs when costing loads and stores to memory.

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 1b21ecc..d158260 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -142,6 +142,7 @@ static bool aarch64_const_vec_all_same_int_p (rtx,
 
 static bool aarch64_vectorize_vec_perm_const_ok (enum machine_mode vmode,
 						 const unsigned char *sel);
+static int aarch64_address_cost (rtx, enum machine_mode, addr_space_t, bool);
 
 /* The processor for which instructions should be scheduled.  */
 enum aarch64_processor aarch64_tune = cortexa53;
@@ -4835,7 +4836,19 @@ aarch64_rtx_costs (rtx x, int code, int outer ATTRIBUTE_UNUSED,
 	{
 	case MEM:
 	  if (speed)
-	    *cost += extra_cost->ldst.store;
+	    {
+	      rtx address = XEXP (op0, 0);
+	      if (GET_MODE_CLASS (mode) == MODE_INT)
+		*cost += extra_cost->ldst.store;
+	      else if (mode == SFmode)
+		*cost += extra_cost->ldst.storef;
+	      else if (mode == DFmode)
+		*cost += extra_cost->ldst.stored;
+
+	      *cost +=
+		COSTS_N_INSNS (aarch64_address_cost (address, mode,
+						     0, speed));
+	    }
 
 	  *cost += rtx_cost (op1, SET, 1, speed);
 	  return true;
@@ -4948,7 +4961,22 @@ aarch64_rtx_costs (rtx x, int code, int outer ATTRIBUTE_UNUSED,
 
     case MEM:
       if (speed)
-	*cost += extra_cost->ldst.load;
+	{
+	  /* For loads we want the base cost of a load, plus an
+	     approximation for the additional cost of the addressing
+	     mode.  */
+	  rtx address = XEXP (x, 0);
+	  if (GET_MODE_CLASS (mode) == MODE_INT)
+	    *cost += extra_cost->ldst.load;
+	  else if (mode == SFmode)
+	    *cost += extra_cost->ldst.loadf;
+	  else if (mode == DFmode)
+	    *cost += extra_cost->ldst.loadd;
+
+	  *cost +=
+		COSTS_N_INSNS (aarch64_address_cost (address, mode,
+						     0, speed));
+	}
 
       return true;