Hello,
This adjusts the cost calculations for shifts on SH.
I tried out Richard's advice
( http://gcc.gnu.org/ml/gcc-patches/2012-07/msg01206.html )
and it seems to work OK to just leave out the mentioned CONST_INT_P
case.
Tested on rev 189870 with
make -k check RUNTESTFLAGS="--target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a/-mb,-m2a-single/-mb,-m4/-ml,-m4/-mb,-m4-single/-ml,
-m4-single/-mb,-m4a-single/-ml,-m4a-single/-mb}"
and no new failures.
I've also confirmed that the example function in
tree-switch-conversion.c:184 now is transformed as expected. The CSiBE
set shows a few improvements here and there, where these kind of
transformations can be applied for when dynamic shifts are available
(SH3+). For SH2 (no dynamic shifts) there also seem to be some minor
improvements.
OK?
Cheers,
Oleg
ChangeLog
PR target/54089
* config/sh/sh.c (shiftcosts): Remove case where first operand
is a const_int. Move COSTS_N_INSNS usage into caller ...
(sh_rtx_costs) ... here. Return false when shiftcosts cannot be
calculated instead of MAX_COST.
Index: gcc/config/sh/sh.c
===================================================================
--- gcc/config/sh/sh.c (revision 189877)
+++ gcc/config/sh/sh.c (working copy)
@@ -2859,26 +2859,22 @@
{
int value;
- /* There is no pattern for constant first operand. */
- if (CONST_INT_P (XEXP (x, 0)))
- return MAX_COST;
-
if (TARGET_SHMEDIA)
- return COSTS_N_INSNS (1);
+ return 1;
if (GET_MODE_SIZE (GET_MODE (x)) > UNITS_PER_WORD)
{
if (GET_MODE (x) == DImode
&& CONST_INT_P (XEXP (x, 1))
&& INTVAL (XEXP (x, 1)) == 1)
- return COSTS_N_INSNS (2);
+ return 2;
/* Everything else is invalid, because there is no pattern for it. */
- return MAX_COST;
+ return -1;
}
/* If shift by a non constant, then this will be expensive. */
if (!CONST_INT_P (XEXP (x, 1)))
- return COSTS_N_INSNS (SH_DYNAMIC_SHIFT_COST);
+ return SH_DYNAMIC_SHIFT_COST;
/* Otherwise, return the true cost in instructions. Cope with out of range
shift counts more or less arbitrarily. */
@@ -2887,13 +2883,14 @@
if (GET_CODE (x) == ASHIFTRT)
{
int cost = ashiftrt_insns[value];
- /* If SH3, then we put the constant in a reg and use shad. */
+ /* If dynamic shifts are available and profitable in this case, then we
+ put the constant in a reg and use shad. */
if (cost > 1 + SH_DYNAMIC_SHIFT_COST)
cost = 1 + SH_DYNAMIC_SHIFT_COST;
- return COSTS_N_INSNS (cost);
+ return cost;
}
else
- return COSTS_N_INSNS (shift_insns[value]);
+ return shift_insns[value];
}
/* Return the cost of an AND/XOR/IOR operation. */
@@ -3147,8 +3144,13 @@
case ASHIFT:
case ASHIFTRT:
case LSHIFTRT:
- *total = shiftcosts (x);
- return true;
+ {
+ int cost = shiftcosts (x);
+ if (cost < 0)
+ return false;
+ *total = COSTS_N_INSNS (cost);
+ return true;
+ }
case DIV:
case UDIV:
