freedreno: Improve the pi approximations in trig lowering.

When comparing our sin/cos behavior to the closed source driver, I
noticed that we were off by a bit (or, in the case of 1/2pi, 3 bits).

Fixes:
dEQP-GLES3.functional.shaders.random.trigonometric.vertex.52
dEQP-GLES3.functional.shaders.random.all_features.vertex.0

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>

diff --git a/src/freedreno/ir3/ir3_nir_trig.py b/src/freedreno/ir3/ir3_nir_trig.py
index 3968aea543c30bbc11f7c9de59efce1803f337fc..7e2d554b0d0fcf0cab5b9b675c845c105cf463db 100644 (file)
--- a/src/freedreno/ir3/ir3_nir_trig.py
+++ b/src/freedreno/ir3/ir3_nir_trig.py
@@ -26,8 +26,8 @@ import argparse
 import sys
 
 trig_workarounds = [
-   (('fsin', 'x'), ('fsin', ('fsub', ('fmul', 6.283185, ('ffract', ('fadd', ('fmul', 0.159155, 'x'), 0.5))), 3.141593))),
-   (('fcos', 'x'), ('fcos', ('fsub', ('fmul', 6.283185, ('ffract', ('fadd', ('fmul', 0.159155, 'x'), 0.5))), 3.141593))),
+   (('fsin', 'x'), ('fsin', ('fsub', ('fmul', 6.2831853, ('ffract', ('fadd', ('fmul', 0.15915494, 'x'), 0.5))), 3.14159265))),
+   (('fcos', 'x'), ('fcos', ('fsub', ('fmul', 6.2831853, ('ffract', ('fadd', ('fmul', 0.15915494, 'x'), 0.5))), 3.14159265))),
 ]