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[AArch64] Avoid extraneous CMP in I{444,422}ToARGBRow_SVE2 impl

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We can use subs to set condition flags as part of the subtract, no need
for a separate compare instruction. No performance difference observed
from this change, but it now matches the other SVE2 kernels.

Also remove unnecessary volatile from asm blocks.

Bug: libyuv:973
Change-Id: I9bb4f5f1101086602f7d5223feaeae0fb63b385c
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/5463951
Reviewed-by: Frank Barchard <fbarchard@chromium.org>
Commit-Queue: Frank Barchard <fbarchard@chromium.org>
This commit is contained in:
George Steed 2024-04-19 13:24:52 +01:00 committed by libyuv LUCI CQ
parent f483007b9a
commit ce32eb773f
1 changed files with 21 additions and 16 deletions
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37
source/row_sve.cc
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@ -85,29 +85,32 @@ void I444ToARGBRow_SVE2(const uint8_t* src_y,
const struct YuvConstants* yuvconstants,
int width) {
uint64_t vl;
asm volatile(
"cnth %[vl] \n"
asm("cnth %[vl] \n"
"ptrue p0.b \n" YUVTORGB_SVE_SETUP
"dup z19.b, #255 \n" /* A */
"cmp %w[width], %w[vl] \n"
"b.le 2f \n"
"subs %w[width], %w[width], %w[vl] \n"
"b.lt 2f \n"
// Run bulk of computation with an all-true predicate to avoid predicate
// generation overhead.
"ptrue p1.h \n"
"1: \n" READYUV444_SVE
I4XXTORGB_SVE RGBTORGBA8_SVE
"sub %w[width], %w[width], %w[vl] \n"
"subs %w[width], %w[width], %w[vl] \n"
"st2h {z16.h, z17.h}, p1, [%[dst_argb]] \n"
"add %[dst_argb], %[dst_argb], %[vl], lsl #2 \n"
"cmp %w[width], %w[vl] \n"
"b.gt 1b \n"
"b.ge 1b \n"
"2: \n"
"adds %w[width], %w[width], %w[vl] \n"
"b.eq 99f \n"
// Calculate a predicate for the final iteration to deal with the tail.
"2: \n"
"whilelt p1.h, wzr, %w[width] \n" READYUV444_SVE
I4XXTORGB_SVE RGBTORGBA8_SVE
"st2h {z16.h, z17.h}, p1, [%[dst_argb]] \n"
"99: \n"
: [src_y] "+r"(src_y), // %[src_y]
[src_u] "+r"(src_u), // %[src_u]
[src_v] "+r"(src_v), // %[src_v]
@ -126,30 +129,32 @@ void I422ToARGBRow_SVE2(const uint8_t* src_y,
const struct YuvConstants* yuvconstants,
int width) {
uint64_t vl;
asm volatile(
"cnth %[vl] \n"
asm("cnth %[vl] \n"
"ptrue p0.b \n" YUVTORGB_SVE_SETUP
"dup z19.b, #255 \n" /* A */
"cmp %w[width], %w[vl] \n"
"b.le 2f \n"
"subs %w[width], %w[width], %w[vl] \n"
"b.lt 2f \n"
// Run bulk of computation with an all-true predicate to avoid predicate
// generation overhead.
"ptrue p1.h \n"
"sub %w[width], %w[width], %w[vl] \n"
"1: \n" READYUV422_SVE
I4XXTORGB_SVE RGBTORGBA8_SVE
"subs %w[width], %w[width], %w[vl] \n"
"st2h {z16.h, z17.h}, p1, [%[dst_argb]] \n"
"add %[dst_argb], %[dst_argb], %[vl], lsl #2 \n"
"b.gt 1b \n"
"add %w[width], %w[width], %w[vl] \n"
"b.ge 1b \n"
"2: \n"
"adds %w[width], %w[width], %w[vl] \n"
"b.eq 99f \n"
// Calculate a predicate for the final iteration to deal with the tail.
"2: \n"
"whilelt p1.h, wzr, %w[width] \n" READYUV422_SVE
I4XXTORGB_SVE RGBTORGBA8_SVE
"st2h {z16.h, z17.h}, p1, [%[dst_argb]] \n"
"99: \n"
: [src_y] "+r"(src_y), // %[src_y]
[src_u] "+r"(src_u), // %[src_u]
[src_v] "+r"(src_v), // %[src_v]