nir/algebraic: Add helpers and a rule involving wrapping

[mesa.git] / src / compiler / nir / nir_opt_algebraic.py

diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
index 45e8779e16e09329bfd5080faf9add12d40c86ac..8b78688705210e3d813441b4a06b3147e5f26dca 100644 (file)
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -761,6 +761,9 @@ optimizations.extend([
    (('~fadd', '#a', ('fneg', ('fadd', 'b(is_not_const)', '#c'))), ('fadd', ('fadd', a, ('fneg', c)), ('fneg', b))),
    (('iadd', '#a', ('iadd', 'b(is_not_const)', '#c')), ('iadd', ('iadd', a, c), b)),
 
+   # Drop mul-div by the same value when there's no wrapping.
+   (('idiv', ('imul(no_signed_wrap)', a, b), b), a),
+
    # By definition...
    (('bcsel', ('ige', ('find_lsb', a), 0), ('find_lsb', a), -1), ('find_lsb', a)),
    (('bcsel', ('ige', ('ifind_msb', a), 0), ('ifind_msb', a), -1), ('ifind_msb', a)),