nir/algebraic: support for power-of-two optimizations

Some optimizations, like converting integer multiply/divide into left/
right shifts, have additional constraints on the search expression.
Like requiring that a variable is a constant power of two.  Support
these cases by allowing a fxn name to be appended to the search var
expression (ie. "a#32(is_power_of_two)").

Signed-off-by: Rob Clark <robclark@freedesktop.org>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/compiler/nir/nir_search.h b/src/compiler/nir/nir_search.h
index a500feb..f55d797 100644
--- a/src/compiler/nir/nir_search.h
+++ b/src/compiler/nir/nir_search.h
@@ -68,6 +68,16 @@ typedef struct {
     * never match anything.
     */
    nir_alu_type type;
+
+   /** Optional condition fxn ptr
+    *
+    * This is only allowed in search expressions, and allows additional
+    * constraints to be placed on the match.  Typically used for 'is_constant'
+    * variables to require, for example, power-of-two in order for the search
+    * to match.
+    */
+   bool (*cond)(nir_alu_instr *instr, unsigned src,
+                unsigned num_components, const uint8_t *swizzle);
 } nir_search_variable;
 
 typedef struct {