SH: Fix cost estimation of mem load/store

For memory loads/stores (that contain a MEM rtx) sh_rtx_costs would wrongly
report a cost lower than 1 insn which is not accurate as it makes loads/stores
appear cheaper than simple arithmetic insns.  The cost of a load/store insn is
at least 1 insn plus the cost of the address expression (some addressing modes
can be considered more expensive than others due to additional constraints).

gcc/ChangeLog:

	PR target/113533
	* config/sh/sh.cc (sh_rtx_costs): Adjust cost estimation of MEM rtx
	to be always at least COST_N_INSNS (1).  Forward speed argument to
	sh_address_cost.

Co-authored-by: Roger Sayle <roger@nextmovesoftware.com>

diff --git a/gcc/config/sh/sh.cc b/gcc/config/sh/sh.cc
index 7391b8df5830da835d888b7841167cb33d09d6a8..6ad202fd4263f7a690e06f6140611fed99c34a2c 100644 (file)
--- a/gcc/config/sh/sh.cc
+++ b/gcc/config/sh/sh.cc
@@ -3231,7 +3231,7 @@ multcosts (rtx x ATTRIBUTE_UNUSED)
 static bool
 sh_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED, int outer_code,
              int opno ATTRIBUTE_UNUSED,
-             int *total, bool speed ATTRIBUTE_UNUSED)
+             int *total, bool speed)
 {
   int code = GET_CODE (x);
 
@@ -3264,10 +3264,12 @@ sh_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED, int outer_code,
         }
       return false;
 
-    /* The cost of a mem access is mainly the cost of the address mode.  */
+    /* The cost of a mem access is mainly the cost of the address mode on top
+       of the cost of the load/store insn itself.  */
     case MEM:
       *total = sh_address_cost (XEXP (x, 0), GET_MODE (x), MEM_ADDR_SPACE (x),
-                               true);
+                               speed)
+              + COSTS_N_INSNS (1);
       return true;
 
     case IF_THEN_ELSE:
@@ -3317,7 +3319,8 @@ sh_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED, int outer_code,
        {
          *total = sh_address_cost (XEXP (XEXP (x, 0), 0),
                                    GET_MODE (XEXP (x, 0)),
-                                   MEM_ADDR_SPACE (XEXP (x, 0)), true);
+                                   MEM_ADDR_SPACE (XEXP (x, 0)), speed)
+                  + COSTS_N_INSNS (1);
          return true;
        }
       return false;
@@ -3335,7 +3338,8 @@ sh_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED, int outer_code,
          /* Handle SH2A's movu.b and movu.w insn.  */
          *total = sh_address_cost (XEXP (XEXP (x, 0), 0), 
                                    GET_MODE (XEXP (x, 0)), 
-                                   MEM_ADDR_SPACE (XEXP (x, 0)), true);
+                                   MEM_ADDR_SPACE (XEXP (x, 0)), speed)
+                  + COSTS_N_INSNS (1);
          return true;
        }
       return false;
@@ -3350,14 +3354,16 @@ sh_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED, int outer_code,
            {
              *total = sh_address_cost (XEXP (XEXP (xx, 0), 0), 
                                        GET_MODE (XEXP (xx, 0)),
-                                       MEM_ADDR_SPACE (XEXP (xx, 0)), true);
+                                       MEM_ADDR_SPACE (XEXP (xx, 0)), speed);
+                      + COSTS_N_INSNS (1);
              return true;
            }
          if (GET_CODE (xx) == SET && MEM_P (XEXP (xx, 1)))
            {
              *total = sh_address_cost (XEXP (XEXP (xx, 1), 0),
                                        GET_MODE (XEXP (xx, 1)),
-                                       MEM_ADDR_SPACE (XEXP (xx, 1)), true);
+                                       MEM_ADDR_SPACE (XEXP (xx, 1)), speed);
+                      + COSTS_N_INSNS (1);
              return true;
            }
        }