nir: Add identities for the exponential function.

No changes in shader-db.

Reviewed-by: Eric Anholt <eric@anholt.net>

diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index 5b84a4e1cd874cc55414e179d48ef102962fd1f0..db2fe0372062cd4e1dc720ddf72a86272cee3ed2 100644 (file)
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -139,6 +139,12 @@ optimizations = [
    (('fpow', a, 1.0), a),
    (('fpow', a, 2.0), ('fmul', a, a)),
    (('fpow', 2.0, a), ('fexp2', a)),
+   (('fsqrt', ('fexp2', a)), ('fexp2', ('fmul', 0.5, a))),
+   (('fsqrt', ('fexp', a)), ('fexp', ('fmul', 0.5, a))),
+   (('frcp', ('fexp2', a)), ('fexp2', ('fneg', a))),
+   (('frcp', ('fexp', a)), ('fexp', ('fneg', a))),
+   (('frsq', ('fexp2', a)), ('fexp2', ('fmul', -0.5, a))),
+   (('frsq', ('fexp', a)), ('fexp', ('fmul', -0.5, a))),
    # Division and reciprocal
    (('fdiv', 1.0, a), ('frcp', a)),
    (('frcp', ('frcp', a)), a),