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authorSamuel Pitoiset <samuel.pitoiset@gmail.com>2020-02-04 17:25:35 +0100
committerDylan Baker <dylan@pnwbakers.com>2020-02-11 09:27:10 -0800
commit42e7b158a37a6f23b3e5d7b4df68037206b94a16 (patch)
tree61d39263cfe012301e9db1497ecdbf2c0b69bf9a
parent8f630dc7c5483a75fe8fd890be03586dfa79779b (diff)
nir: do not use De Morgan's Law rules for flt and fge
In presence of NaNs, "!(flt(a, b) && flt(c, d))" is NOT EQUAL to "fge(a, b) || fge(c, d)". These optimizations are unsafe for apps that rely on NaN behaviour. pipeline-db (GFX9/LLVM): Totals from affected shaders: SGPRS: 3176 -> 3136 (-1.26 %) VGPRS: 2188 -> 2144 (-2.01 %) Spilled SGPRs: 227 -> 169 (-25.55 %) Code Size: 150572 -> 151800 (0.82 %) bytes Max Waves: 307 -> 310 (0.98 %) pipeline-db (GFX9/ACO): Totals from affected shaders: SGPRS: 18744 -> 18744 (0.00 %) VGPRS: 15576 -> 15580 (0.03 %) Spilled SGPRs: 164 -> 164 (0.00 %) Code Size: 1573012 -> 1576492 (0.22 %) bytes Max Waves: 1534 -> 1532 (-0.13 %) Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2127 Fixes: d1ed4ffe0b7 ("nir: Use De Morgan's Law on logic compounded comparisons") Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com> Reviewed-by: Ian Romanick <ian.d.romanick@intel.com> Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3696> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3696> (cherry picked from commit 8e7728077435c5c5ad8c328761277f8ff3b32112)
-rw-r--r--.pick_status.json2
-rw-r--r--src/compiler/nir/nir_opt_algebraic.py2
2 files changed, 2 insertions, 2 deletions
diff --git a/.pick_status.json b/.pick_status.json
index 5d320ee9517..d8299f420cc 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -13,7 +13,7 @@
"description": "nir: do not use De Morgan's Law rules for flt and fge",
"nominated": true,
"nomination_type": 1,
- "resolution": 0,
+ "resolution": 1,
"master_sha": null,
"because_sha": "d1ed4ffe0b70762477709e699f95c73602f9dc5a"
},
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index e4295d7a9e9..e2371462d1e 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -1153,7 +1153,7 @@ for bit_size in [8, 16, 32, 64]:
('bcsel', ('ilt', a, ('isub', a, b)), intmin, ('isub', a, b))), 'options->lower_add_sat'),
]
-invert = OrderedDict([('feq', 'fne'), ('fne', 'feq'), ('fge', 'flt'), ('flt', 'fge')])
+invert = OrderedDict([('feq', 'fne'), ('fne', 'feq')])
for left, right in itertools.combinations_with_replacement(invert.keys(), 2):
optimizations.append((('inot', ('ior(is_used_once)', (left, a, b), (right, c, d))),