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SH: Fix cost estimation of mem load/store

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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>
This commit is contained in:
Oleg Endo 2024-10-13 11:36:38 +09:00
parent 7ec8b4bf42
commit b717c462b9
1 changed files with 13 additions and 7 deletions
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20
gcc/config/sh/sh.cc
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@ -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;
}
}