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| author |  commit-bot@chromium.org <commit-bot@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> | 2013-08-05 20:25:57 +0000 |
|---|---|---|
| committer | commit-bot@chromium.org <commit-bot@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> | 2013-08-05 20:25:57 +0000 |
| commit | 9772a52f0d9e540d2a360dde2aab0ad41c90b1d8 (patch) | |
| tree | a72b03a99a6528745060c487a1f267c647d64ec6 | |
| parent | 67ed64e9aa70f5a95a2d309f9b73dc0009f3ed8c (diff) | |
Minor sk_memset{16|32}_SSE2 optimization.
Using explicitly indexed references allows some compilers to generate more efficient loops. For gcc 4.6.3:
613c18: 83 ea 10 sub $0x10,%edx
613c1b: 66 0f 7f 07 movdqa %xmm0,(%rdi)
613c1f: 66 0f 7f 47 10 movdqa %xmm0,0x10(%rdi)
613c24: 66 0f 7f 47 20 movdqa %xmm0,0x20(%rdi)
613c29: 66 0f 7f 47 30 movdqa %xmm0,0x30(%rdi)
613c2e: 48 83 c7 40 add $0x40,%rdi
613c32: 83 fa 0f cmp $0xf,%edx
613c35: 7f e1 jg 613c18 <_Z16sk_memset32_SSE2Pjji+0x38>
vs. previous:
613c18: 83 ea 10 sub $0x10,%edx
613c1b: 66 0f 7f 07 movdqa %xmm0,(%rdi)
613c1f: 66 0f 7f 47 10 movdqa %xmm0,0x10(%rdi)
613c24: 66 0f 7f 47 20 movdqa %xmm0,0x20(%rdi)
613c29: 48 83 c7 40 add $0x40,%rdi
613c2d: 83 fa 0f cmp $0xf,%edx
613c30: 66 0f 7f 47 f0 movdqa %xmm0,-0x10(%rdi)
613c35: 7f e1 jg 613c18 <_Z16sk_memset32_SSE2Pjji+0x38>
This yields a 0.2% - 1% improvement with the memset micro benchmarks, presumably due to avoiding a stall on the next store after the %rdi increment.
R=reed@google.com, senorblanco@chromium.org
Author: fmalita@chromium.org
Review URL: https://chromiumcodereview.appspot.com/21703003
git-svn-id: http://skia.googlecode.com/svn/trunk@10545 2bbb7eff-a529-9590-31e7-b0007b416f81
| -rw-r--r-- | src/opts/SkUtils_opts_SSE2.cpp | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/src/opts/SkUtils_opts_SSE2.cpp b/src/opts/SkUtils_opts_SSE2.cpp index 08e4f66948..e22044d39d 100644 --- a/src/opts/SkUtils_opts_SSE2.cpp +++ b/src/opts/SkUtils_opts_SSE2.cpp @@ -25,10 +25,11 @@ void sk_memset16_SSE2(uint16_t *dst, uint16_t value, int count) __m128i *d = reinterpret_cast<__m128i*>(dst); __m128i value_wide = _mm_set1_epi16(value); while (count >= 32) { - _mm_store_si128(d++, value_wide); - _mm_store_si128(d++, value_wide); - _mm_store_si128(d++, value_wide); - _mm_store_si128(d++, value_wide); + _mm_store_si128(d , value_wide); + _mm_store_si128(d + 1, value_wide); + _mm_store_si128(d + 2, value_wide); + _mm_store_si128(d + 3, value_wide); + d += 4; count -= 32; } dst = reinterpret_cast<uint16_t*>(d); @@ -54,10 +55,11 @@ void sk_memset32_SSE2(uint32_t *dst, uint32_t value, int count) __m128i *d = reinterpret_cast<__m128i*>(dst); __m128i value_wide = _mm_set1_epi32(value); while (count >= 16) { - _mm_store_si128(d++, value_wide); - _mm_store_si128(d++, value_wide); - _mm_store_si128(d++, value_wide); - _mm_store_si128(d++, value_wide); + _mm_store_si128(d , value_wide); + _mm_store_si128(d + 1, value_wide); + _mm_store_si128(d + 2, value_wide); + _mm_store_si128(d + 3, value_wide); + d += 4; count -= 16; } dst = reinterpret_cast<uint32_t*>(d); |