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[AArch64 costs 10/18] Improve costs for sign/zero extend operations 

gcc/

	* config/aarch64/aarch64.c (aarch64_rtx_costs): Cost
	ZERO_EXTEND and SIGN_EXTEND better.


Co-Authored-By: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

From-SVN: r210502
This commit is contained in:
James Greenhalgh 2014-05-16 09:01:28 +00:00 committed by James Greenhalgh
parent 268c3b4758
commit b1685e6274
2 changed files with 53 additions and 6 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2014-05-16 James Greenhalgh <james.greenhalgh@arm.com>
Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
* config/aarch64/aarch64.c (aarch64_rtx_costs): Cost
ZERO_EXTEND and SIGN_EXTEND better.
2014-05-16 James Greenhalgh <james.greenhalgh@arm.com>
Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

53
gcc/config/aarch64/aarch64.c
View File

@ -5281,21 +5281,62 @@ cost_minus:
return false;
case ZERO_EXTEND:
if ((GET_MODE (x) == DImode
&& GET_MODE (XEXP (x, 0)) == SImode)
|| GET_CODE (XEXP (x, 0)) == MEM)
op0 = XEXP (x, 0);
/* If a value is written in SI mode, then zero extended to DI
mode, the operation will in general be free as a write to
a 'w' register implicitly zeroes the upper bits of an 'x'
register. However, if this is
(set (reg) (zero_extend (reg)))
we must cost the explicit register move. */
if (mode == DImode
&& GET_MODE (op0) == SImode
&& outer == SET)
{
*cost += rtx_cost (XEXP (x, 0), ZERO_EXTEND, 0, speed);
int op_cost = rtx_cost (XEXP (x, 0), ZERO_EXTEND, 0, speed);
if (!op_cost && speed)
/* MOV. */
*cost += extra_cost->alu.extend;
else
/* Free, the cost is that of the SI mode operation. */
*cost = op_cost;
return true;
}
else if (MEM_P (XEXP (x, 0)))
{
/* All loads can zero extend to any size for free. */
*cost = rtx_cost (XEXP (x, 0), ZERO_EXTEND, param, speed);
return true;
}
/* UXTB/UXTH. */
if (speed)
*cost += extra_cost->alu.extend;
return false;
case SIGN_EXTEND:
if (GET_CODE (XEXP (x, 0)) == MEM)
if (MEM_P (XEXP (x, 0)))
{
*cost += rtx_cost (XEXP (x, 0), SIGN_EXTEND, 0, speed);
/* LDRSH. */
if (speed)
{
rtx address = XEXP (XEXP (x, 0), 0);
*cost += extra_cost->ldst.load_sign_extend;
*cost +=
COSTS_N_INSNS (aarch64_address_cost (address, mode,
0, speed));
}
return true;
}
if (speed)
*cost += extra_cost->alu.extend;
return false;
case ROTATE: