@@ -228,18 +228,18 @@ static enum shift_alg shift_alg_si[2][3][32] = {
/* 8 9 10 11 12 13 14 15 */
/* 16 17 18 19 20 21 22 23 */
/* 24 25 26 27 28 29 30 31 */
- { INL, INL, INL, INL, INL, LOP, LOP, LOP,
+ { INL, INL, INL, INL, INL, INL, INL, LOP,
SPC, LOP, LOP, LOP, LOP, LOP, LOP, SPC,
- SPC, SPC, SPC, SPC, LOP, LOP, LOP, LOP,
- SPC, LOP, LOP, LOP, SPC, SPC, SPC, SPC }, /* SHIFT_ASHIFT */
- { INL, INL, INL, INL, INL, LOP, LOP, LOP,
+ SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC,
+ SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC }, /* SHIFT_ASHIFT */
+ { INL, INL, INL, INL, INL, INL, INL, LOP,
SPC, LOP, LOP, LOP, LOP, LOP, LOP, SPC,
- SPC, SPC, SPC, SPC, LOP, LOP, LOP, LOP,
- SPC, LOP, LOP, LOP, SPC, SPC, SPC, SPC }, /* SHIFT_LSHIFTRT */
- { INL, INL, INL, INL, INL, LOP, LOP, LOP,
+ SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC,
+ SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC }, /* SHIFT_LSHIFTRT */
+ { INL, INL, INL, INL, INL, INL, INL, LOP,
SPC, LOP, LOP, LOP, LOP, LOP, LOP, LOP,
- SPC, SPC, SPC, SPC, LOP, LOP, LOP, LOP,
- SPC, LOP, LOP, LOP, LOP, LOP, LOP, SPC }, /* SHIFT_ASHIFTRT */
+ SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC,
+ SPC, SPC, SPC, SPC, LOP, LOP, LOP, SPC }, /* SHIFT_ASHIFTRT */
},
{
/* TARGET_H8300S */
@@ -343,6 +343,36 @@ h8300_option_override (void)
shift_alg_hi[H8_300H][SHIFT_ASHIFTRT][13] = SHIFT_LOOP;
shift_alg_hi[H8_300H][SHIFT_ASHIFTRT][14] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][5] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][6] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][20] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][21] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][22] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][23] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][25] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][26] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFT][27] = SHIFT_LOOP;
+
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][5] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][6] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][20] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][21] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][22] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][23] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][25] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][26] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_LSHIFTRT][27] = SHIFT_LOOP;
+
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][5] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][6] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][20] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][21] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][22] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][23] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][25] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][26] = SHIFT_LOOP;
+ shift_alg_si[H8_300H][SHIFT_ASHIFTRT][27] = SHIFT_LOOP;
+
/* H8S */
shift_alg_hi[H8_S][SHIFT_ASHIFTRT][14] = SHIFT_LOOP;
}
@@ -3784,7 +3814,7 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
gcc_unreachable ();
}
}
- else if ((TARGET_H8300H && count >= 16 && count <= 19)
+ else if ((TARGET_H8300H && count >= 16 && count <= 23)
|| (TARGET_H8300S && count >= 16 && count <= 21))
{
info->remainder = count - 16;
@@ -3804,7 +3834,7 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
goto end;
}
}
- else if ((TARGET_H8300H && count == 24)
+ else if ((TARGET_H8300H && count >= 24 || count <= 27)
|| (TARGET_H8300S && count >= 24 && count <= 25))
{
info->remainder = count - 24;
As I've mentioned before, the H8/300H can only shift a single bit position at a time. Naturally this means many shifts are implemented as loops. There's a variety of special cases that we can do without loops by using rotates, sub-word moves, etc. The general guidance for the port has been to only use inline or special sequences if they're shorter or just one instruction longer than the loop. This was pretty reasonable guidance for QI/HI mode. It was relaxed a bit about 10 years ago for HImode in particular where the kpit team realized they could save 50-100 cycles for some shifts by allowing 2 instructions of code growth over the loop implementation. But they only re-tuned HImode shifts. There's even bigger benefits for re-tuning SImode shifts. There's cases where we can save close to 200 cycles by allowing 2 additional instructions. This patch re-tunes SImode shifts on the H8/300H primarily by inlining more often or using a special sequence + inlining for residuals. Both cases were already supported and this just uses those existing capabilities more often, so it was trivial to implement. I think there's some cases were entirely new special sequences could be used, but I haven't tried those yet. There'll be a similar follow-up for the H8/S. The gains aren't as spectacular as the H8/S gained shift-by-2 instructions, but they should still be significant. Committed to the trunk after the usual testing and no regressions. Jeff commit 882f1d58bfa56737ff2de84c3cd1e0acfc318b86 Author: Jeff Law <jlaw@localhost.localdomain> Date: Sun Aug 15 00:13:23 2021 -0400 Improve many SImode shifts on the H8/300H As I've mentioned before, the H8/300H can only shift a single bit position at a time. Naturally this means many shifts are implemented as loops. There's a variety of special cases that we can do without loops by using rotates, sub-word moves, etc. The general guidance for the port has been to only use inline or special sequences if they're shorter or just one instruction longer than the loop. This was pretty reasonable guidance for QI/HI mode. It was relaxed a bit about 10 years ago for HImode in particular where the kpit team realized they could save 50-100 cycles for some shifts by allowing 2 instructions of code growth over the loop implementation. But they only re-tuned HImode shifts. There's even bigger benefits for re-tuning SImode shifts. There's cases where we can save close to 200 cycles by allowing 2 additional instructions. This patch re-tunes SImode shifts on the H8/300H primarily by inlining more often or using a special sequence + inlining for residuals. Both cases were already supported and this just uses those existing capabilities more often, so it was trivial to implement. I think there's some cases were entirely new special sequences could be used, but I haven't tried those yet. gcc/ * config/h8300/h8300.c (shift_alg_si): Retune H8/300H shifts to allow a bit more code growth, saving many dozens of cycles. (h8300_option_override): Adjus shift_alg_si if optimizing for code size. (get_shift_alg): Use special + inline shifts for residuals in more cases.