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authorEric Anholt <[email protected]>2018-05-04 14:02:55 -0700
committerEric Anholt <[email protected]>2018-06-06 13:44:28 -0700
commit6a0db5f08ffac7d43a5b937982262f357a21f95b (patch)
tree62cb75c55c8ffacbb39d98d3c428198482b63b34 /src
parentd4c7c3c225b7c34669498c15c2d3186cf6a4647e (diff)
nir: Add lowering for find_lsb.
There is a fairly simple relation to turn this into ufind_msb. Reviewed-by: Matt Turner <[email protected]> Reviewed-by: Ian Romanick <[email protected]>
Diffstat (limited to 'src')
-rw-r--r--src/compiler/nir/nir.h2
-rw-r--r--src/compiler/nir/nir_opt_algebraic.py4
2 files changed, 6 insertions, 0 deletions
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 9fca61f0070..b9426f8eb4e 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -1915,6 +1915,8 @@ typedef struct nir_shader_compiler_options {
bool lower_bfm;
/** Lowers ifind_msb to compare and ufind_msb */
bool lower_ifind_msb;
+ /** Lowers find_lsb to ufind_msb and logic ops */
+ bool lower_find_lsb;
bool lower_uadd_carry;
bool lower_usub_borrow;
/** lowers fneg and ineg to fsub and isub. */
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index f6685977f3a..db907df8545 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -559,6 +559,10 @@ optimizations = [
('ufind_msb', ('bcsel', ('ilt', 'value', 0), ('inot', 'value'), 'value')),
'options->lower_ifind_msb'),
+ (('find_lsb', 'value'),
+ ('ufind_msb', ('iand', 'value', ('ineg', 'value'))),
+ 'options->lower_find_lsb'),
+
(('extract_i8', a, 'b@32'),
('ishr', ('ishl', a, ('imul', ('isub', 3, b), 8)), 24),
'options->lower_extract_byte'),