Build mesa 803 completed
Commit 65fbc43d54 by Kenneth Graunke on 1/27/2016 8:21 PM:
i965: Add an INTEL_PRECISE_TRIG=1 option to fix SIN/COS output range.\n\nThe SIN and COS instructions on Intel hardware can produce values\nslightly outside of the [-1.0, 1.0] range for a small set of values.\nObviously, this can break everyone's expectations about trig functions.\n\nAccording to an internal presentation, the COS instruction can produce\na value up to 1.000027 for inputs in the range (0.08296, 0.09888). One\nsuggested workaround is to multiply by 0.99997, scaling down the\namplitude slightly. Apparently this also minimizes the error function,\nreducing the maximum error from 0.00006 to about 0.00003.\n\nWhen enabled, fixes 16 dEQP precision tests\n\n dEQP-GLES31.functional.shaders.builtin_functions.precision.\n {cos,sin}.{highp,mediump}_compute.{scalar,vec2,vec4,vec4}.\n\nat the cost of making every sin and cos call more expensive (about\ntwice the number of cycles on recent hardware). Enabling this\noption has been shown to reduce GPUTest Volplosion performance by\nabout 10%.\n\nSigned-off-by: Kenneth Graunke <[email protected]>\nReviewed-by: Matt Turner <[email protected]>\nReviewed-by: Jason Ekstrand <[email protected]>
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