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Cycles: workaround for noise performance regression in CUDA 5.5

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Use manual ternary operation widening in grad(). Without it nvcc 5.5 produces multiple branch splits with very big branches (because of inlining). This solves 19% performance regression for BMW1M-MikePan.blend.

Also remove one redundant instruction in perlin SSE (when h == 12 or h == 14, then h is always >= 4).

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D190
This commit is contained in:
Sv. Lockal 2014-01-08 22:25:55 +04:00
parent 61c9cacbd7
commit 20b046d763
1 changed files with 5 additions and 5 deletions
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10
intern/cycles/kernel/svm/svm_noise.h
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@ -167,7 +167,8 @@ ccl_device float grad(int hash, float x, float y, float z)
// use vectors pointing to the edges of the cube // use vectors pointing to the edges of the cube
int h = hash & 15; int h = hash & 15;
float u = h<8 ? x : y; float u = h<8 ? x : y;
float v = h<4 ? y : h == 12 || h == 14 ? x : z; float vt = ((h == 12) | (h == 14)) ? x : z;
float v = h < 4 ? y : vt;
return ((h&1) ? -u : u) + ((h&2) ? -v : v); return ((h&1) ? -u : u) + ((h&2) ? -v : v);
} }
@ -185,11 +186,10 @@ ccl_device_inline __m128 grad_sse(const __m128i *hash, const __m128 *x, const __
__m128i case_vy = _mm_cmplt_epi32(h, _mm_set1_epi32(4)); // 0xffffffff if h < 4 else 0 __m128i case_vy = _mm_cmplt_epi32(h, _mm_set1_epi32(4)); // 0xffffffff if h < 4 else 0
__m128i case_h12_raw = _mm_cmpeq_epi32(h, _mm_set1_epi32(12)); // 0xffffffff if h == 12 else 0 __m128i case_h12 = _mm_cmpeq_epi32(h, _mm_set1_epi32(12)); // 0xffffffff if h == 12 else 0
__m128i case_h14_raw = _mm_cmpeq_epi32(h, _mm_set1_epi32(14)); // 0xffffffff if h == 14 else 0 __m128i case_h14 = _mm_cmpeq_epi32(h, _mm_set1_epi32(14)); // 0xffffffff if h == 14 else 0
__m128i case_vxtmp = _mm_or_si128(case_h12_raw, case_h14_raw); // 0xffffffff if h == 12 or h == 14 else 0 __m128i case_vx = _mm_or_si128(case_h12, case_h14); // 0xffffffff if h == 12 or h == 14 else 0
__m128i case_vx = _mm_andnot_si128(case_vy, case_vxtmp); // 0xffffffff if (h == 12 or h == 14) and not(h<4)
__m128 v = blend(_mm_castsi128_ps(case_vy), *y, blend(_mm_castsi128_ps(case_vx), *x, *z)); // v = h<4 ? y : h == 12 || h == 14 ? x : z __m128 v = blend(_mm_castsi128_ps(case_vy), *y, blend(_mm_castsi128_ps(case_vx), *x, *z)); // v = h<4 ? y : h == 12 || h == 14 ? x : z