Module: Mesa
Branch: master
Commit: 5d85a0a55b8c061fa6644ac24163542e3025834c
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=5d85a0a55b8c061fa6644ac24163542e3025834c
Author: Alyssa Rosenzweig <aly...@rosenzweig.io>
Date: Wed May 2 02:04:55 2018 +0000
nir: Implement optional b2f->iand lowering
This pass is required by the Midgard compiler; our instruction set uses
NIR-style booleans (~0 for true) but lacks a dedicated b2f instruction.
Normally, this lowering pass would be implemented in a backend-specific
algebraic pass, but this conflicts with the existing iand->b2f pass in
nir_opt_algebraic.py, hanging the compiler. This patch thus makes the
existing pass optional (default on -- all other backends should remain
unaffected), adding an optional pass for lowering the opposite
direction.
v2: Defer lowering until late algebraic optimisations to allow
optimising the b2f instruction itself.
Signed-off-by: Alyssa Rosenzweig <aly...@rosenzweig.io>
Reviewed-by: Matt Turner <matts...@gmail.com>
Reviewed-by: Christian Gmeiner <christian.gmei...@gmail.com>
---
src/compiler/nir/nir.h | 3 +++
src/compiler/nir/nir_opt_algebraic.py | 5 ++++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index a379928cdc..f6086bd6c0 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -1894,6 +1894,9 @@ typedef struct nir_shader_compiler_options {
/** enables rules to lower idiv by power-of-two: */
bool lower_idiv;
+ /* lower b2f to iand */
+ bool lower_b2f;
+
/* Does the native fdot instruction replicate its result for four
* components? If so, then opt_algebraic_late will turn all fdotN
* instructions into fdot_replicatedN instructions.
diff --git a/src/compiler/nir/nir_opt_algebraic.py
b/src/compiler/nir/nir_opt_algebraic.py
index 96232f0e54..909ea3daf4 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -321,7 +321,7 @@ optimizations = [
(('imul', ('b2i', a), ('b2i', b)), ('b2i', ('iand', a, b))),
(('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
(('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a, b))),
- (('iand', 'a@bool', 1.0), ('b2f', a)),
+ (('iand', 'a@bool', 1.0), ('b2f', a), '!options->lower_b2f'),
# True/False are ~0 and 0 in NIR. b2i of True is 1, and -1 is ~0 (True).
(('ineg', ('b2i@32', a)), a),
(('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
@@ -724,6 +724,9 @@ late_optimizations = [
# we do these late so that we don't get in the way of creating ffmas
(('fmin', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c',
b)), ('fadd', c, ('fmin', a, b))),
(('fmax', ('fadd(is_used_once)', '#c', a), ('fadd(is_used_once)', '#c',
b)), ('fadd', c, ('fmax', a, b))),
+
+ # Lowered for backends without a dedicated b2f instruction
+ (('b2f@32', a), ('iand', a, 1.0), 'options->lower_b2f'),
]
print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
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