nir: Add a few more algebraic optimizations to help address calculation.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9201>

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 1444be1..5938561 100644 (file)
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -340,9 +340,15 @@ optimizations.extend([
    # instruction or a constant offset field for in load / store instructions.
    (('ishl', ('iadd', a, '#b'), '#c'), ('iadd', ('ishl', a, c), ('ishl', b, c))),
 
-   # (a + #b) * #c
+   # (a + #b) * #c => (a * #c) + (#b * #c)
    (('imul', ('iadd(is_used_once)', a, '#b'), '#c'), ('iadd', ('imul', a, c), ('imul', b, c))),
 
+   # ((a + #b) + c) * #d => ((a + c) * #d) + (#b * #d)
+   (('imul', ('iadd(is_used_once)', ('iadd(is_used_once)', a, '#b'), c), '#d'),
+    ('iadd', ('imul', ('iadd', a, c), d), ('imul', b, d))),
+   (('ishl', ('iadd(is_used_once)', ('iadd(is_used_once)', a, '#b'), c), '#d'),
+    ('iadd', ('ishl', ('iadd', a, c), d), ('ishl', b, d))),
+
    # Comparison simplifications
    (('~inot', ('flt', a, b)), ('fge', a, b)),
    (('~inot', ('fge', a, b)), ('flt', a, b)),