Mesa (master): nir: Add a flag for lowering ffma.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: e5ecf8e4272522e1950d1d4318df19377bf49ae1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=e5ecf8e4272522e1950d1d4318df19377bf49ae1

Author: Eric Anholt <eric at anholt.net>
Date:   Fri Jan 30 13:49:48 2015 -0800

nir: Add a flag for lowering ffma.

vc4 cse/algebraic-disabled stats:
total uniforms in shared programs: 13966 -> 13791 (-1.25%)
uniforms in affected programs:     435 -> 260 (-40.23%)
total instructions in shared programs: 44732 -> 44356 (-0.84%)
instructions in affected programs:     9599 -> 9223 (-3.92%)

v2: Rebase to master (no TGSI->NIR present)

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org> (v1)

---

 src/glsl/nir/nir.h                |    1 +
 src/glsl/nir/nir_opt_algebraic.py |    3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 6448d4a..7be1abb 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1327,6 +1327,7 @@ typedef struct nir_function {
                   exec_list_get_head(&(func)->overload_list), node)
 
 typedef struct nir_shader_compiler_options {
+   bool lower_ffma;
    bool lower_fpow;
    bool lower_fsqrt;
    /** lowers fneg and ineg to fsub and isub. */
diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index 8d5c03b..83a02b6 100644
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -71,7 +71,8 @@ optimizations = [
    (('flrp', a, b, 1.0), b),
    (('flrp', a, a, b), a),
    (('flrp', 0.0, a, b), ('fmul', a, b)),
-   (('fadd', ('fmul', a, b), c), ('ffma', a, b, c)),
+   (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options->lower_ffma'),
+   (('fadd', ('fmul', a, b), c), ('ffma', a, b, c), '!options->lower_ffma'),
    # Comparison simplifications
    (('inot', ('flt', a, b)), ('fge', a, b)),
    (('inot', ('fge', a, b)), ('flt', a, b)),