Mesa (master): nir: Add algebraic opt for int comparisons with identical operands.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 56e21647e20db8e3708001a8600c3d8e7d12d841
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=56e21647e20db8e3708001a8600c3d8e7d12d841

Author: Eric Anholt <eric at anholt.net>
Date:   Fri Feb  6 17:12:59 2015 -0800

nir: Add algebraic opt for int comparisons with identical operands.

No change on shader-db on i965.

v2: Reword the comment due to feedback from Erik Faye-Lund

Reviewed-by: Connor Abbott <cwabbott0 at gmail.com> (v1)
Reviewed-by: Jason Ekstrand <jason.ekstrand at intel.com> (v1)

---

 src/glsl/nir/nir_opt_algebraic.py |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index a5fe19a..2b4259e 100644
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -83,6 +83,15 @@ optimizations = [
    (('fne', ('fadd', a, b), 0.0), ('fne', a, ('fneg', b))),
    (('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
    (('fmin', ('fmax', a, 0.0), 1.0), ('fsat', a)),
+   # Comparison with the same args.  Note that these are not done for
+   # the float versions because NaN always returns false on float
+   # inequalities.
+   (('ilt', a, a), False),
+   (('ige', a, a), True),
+   (('ieq', a, a), True),
+   (('ine', a, a), False),
+   (('ult', a, a), False),
+   (('uge', a, a), True),
    # Logical and bit operations
    (('fand', a, 0.0), 0.0),
    (('iand', a, a), a),