Mesa (master): Revert "nir: Replace an odd comparison involving fmin of -b2f"

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Module: Mesa
Branch: master
Commit: 314a40c902c6e92b9d6ba0e9b43708d7e1fa9f00
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=314a40c902c6e92b9d6ba0e9b43708d7e1fa9f00

Author: Ian Romanick <ian.d.romanick at intel.com>
Date:   Thu Jun 11 18:48:41 2020 -0700

Revert "nir: Replace an odd comparison involving fmin of -b2f"

I originally noticed that 3b308147916 ("nir/algebraic: Optimize 1-bit
Booleans") caused this pattern no longer be matched by incorrectly
replacing b at 32 with b at 1.  Making that correct had no effect on
shader-db.  When this pattern originally was added, it only affected 4
shaders, so it's not worth the effort to debug further.

This reverts commit f50400cc8040cf2d07de97e76d9b1ed144c5c8b4.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6358>

---

 src/compiler/nir/nir_opt_algebraic.py | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 7dd1820d584..5ff51f9746f 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -431,19 +431,6 @@ optimizations.extend([
    (('ieq', ('iadd', a, b), a), ('ieq', b, 0)),
    (('ine', ('iadd', a, b), a), ('ine', b, 0)),
 
-   # fmin(-b2f(a), b) >= 0.0
-   # -b2f(a) >= 0.0 && b >= 0.0
-   # -b2f(a) == 0.0 && b >= 0.0    -b2f can only be 0 or -1, never >0
-   # b2f(a) == 0.0 && b >= 0.0
-   # a == False && b >= 0.0
-   # !a && b >= 0.0
-   #
-   # The fge in the second replacement is not a typo.  I leave the proof that
-   # "fmin(-b2f(a), b) >= 0 <=> fmin(-b2f(a), b) == 0" as an exercise for the
-   # reader.
-   (('fge', ('fmin', ('fneg', ('b2f', 'a at 1')), 'b at 1'), 0.0), ('iand', ('inot', a), ('fge', b, 0.0))),
-   (('feq', ('fmin', ('fneg', ('b2f', 'a at 1')), 'b at 1'), 0.0), ('iand', ('inot', a), ('fge', b, 0.0))),
-
    (('feq', ('b2f', 'a at 1'), 0.0), ('inot', a)),
    (('~fneu', ('b2f', 'a at 1'), 0.0), a),
    (('ieq', ('b2i', 'a at 1'), 0),   ('inot', a)),