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authorKenneth Graunke <kenneth@whitecape.org>2016-01-05 05:09:46 -0800
committerKenneth Graunke <kenneth@whitecape.org>2016-01-05 19:22:11 -0800
commit7295f4fcc2b2dd1bc6a8d1d834774b8152a029cf (patch)
tree948332ade1aa90a7ed959f4d5e44edeaa8cfbf0b
parentbd21b54607615605b6335282029687bb0885f4ad (diff)
nir: Add a lower_fdiv option, turn fdiv into fmul/frcp.
The nir_opt_algebraic rule (('fadd', ('flog2', a), ('fneg', ('flog2', b))), ('flog2', ('fdiv', a, b))), can produce new fdiv operations, which need to be lowered on i965, as we don't actually implement fdiv. (Normally, we handle this in GLSL IR's lower_instructions pass, but in the above case we introduce an fdiv after that point. So, make NIR do it for us.) Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com> Reviewed-by: Matt Turner <mattst88@gmail.com> Cc: mesa-stable@lists.freedesktop.org
-rw-r--r--src/glsl/nir/nir.h1
-rw-r--r--src/glsl/nir/nir_opt_algebraic.py1
-rw-r--r--src/mesa/drivers/dri/i965/brw_shader.cpp1
3 files changed, 3 insertions, 0 deletions
diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 4286738254..fed8a97341 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1440,6 +1440,7 @@ typedef struct nir_function {
} nir_function;
typedef struct nir_shader_compiler_options {
+ bool lower_fdiv;
bool lower_ffma;
bool lower_flrp;
bool lower_fpow;
diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py
index 1fdad3d78a..c553de577e 100644
--- a/src/glsl/nir/nir_opt_algebraic.py
+++ b/src/glsl/nir/nir_opt_algebraic.py
@@ -183,6 +183,7 @@ optimizations = [
(('fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
# Division and reciprocal
(('fdiv', 1.0, a), ('frcp', a)),
+ (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
(('frcp', ('frcp', a)), a),
(('frcp', ('fsqrt', a)), ('frsq', a)),
(('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
index d4b6410815..4bd24a70b5 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -97,6 +97,7 @@ brw_compiler_create(void *mem_ctx, const struct brw_device_info *devinfo)
nir_shader_compiler_options *nir_options =
rzalloc(compiler, nir_shader_compiler_options);
nir_options->native_integers = true;
+ nir_options->lower_fdiv = true;
/* In order to help allow for better CSE at the NIR level we tell NIR
* to split all ffma instructions during opt_algebraic and we then
* re-combine them as a later step.