Mesa (master): nir: add address calc related opt rules

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Module: Mesa
Branch: master
Commit: 1bdde313926b698d9959294f1563264ead532b46
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1bdde313926b698d9959294f1563264ead532b46

Author: Rob Clark <robdclark at chromium.org>
Date:   Thu Sep 26 10:34:51 2019 -0700

nir: add address calc related opt rules

Signed-off-by: Rob Clark <robdclark at chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg at google.com>
Reviewed-by: Eduardo Lima Mitev <elima at igalia.com>

---

 src/compiler/nir/nir_opt_algebraic.py | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 7bac217c3e1..fa9ae87b7d7 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -1117,6 +1117,22 @@ optimizations.extend([
    # for now, unconditionally convert amul to imul, this will
    # change in the following patch
    (('amul', a, b), ('imul', a, b)),
+
+   (('imad24_ir3', a, b, 0), ('imul24', a, b)),
+   (('imad24_ir3', a, 0, c), (c)),
+   (('imad24_ir3', a, 1, c), ('iadd', a, c)),
+
+   # if first two srcs are const, crack apart the imad so constant folding
+   # can clean up the imul:
+   # TODO ffma should probably get a similar rule:
+   (('imad24_ir3', '#a', '#b', c), ('iadd', ('imul', a, b), c)),
+
+   # These will turn 24b address/offset calc back into 32b shifts, but
+   # it should be safe to get back some of the bits of precision that we
+   # already decided were no necessary:
+   (('imul24', a, '#b at 32(is_pos_power_of_two)'), ('ishl', a, ('find_lsb', b)), '!options->lower_bitops'),
+   (('imul24', a, '#b at 32(is_neg_power_of_two)'), ('ineg', ('ishl', a, ('find_lsb', ('iabs', b)))), '!options->lower_bitops'),
+   (('imul24', a, 0), (0)),
 ])
 
 # bit_size dependent lowerings