[Mesa-dev] [PATCH] mesa/st: only convert AND(a, NOT(b)) into MAD when not using native integers

[Ilia Mirkin]

Native integers imply a somewhat different handling of booleans. Instead
of being 1.0/0.0 floats, they are 0 (true) / -1 (false) integers. As such
the original optimization no longer applies.

Reported-by: Glenn Kennard <glenn.kennard at gmail.com>
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

This fixes builtin-gl-sample-mask on nvc0, and I presume radeonsi as well. The
code being generated was a

 31:   UMAD TEMP[16], TEMP[15].xxxx, -TEMP[6].xxxx, TEMP[15].xxxx

instead of

 27:   NOT TEMP[14].x, TEMP[6].xxxx
...
 32:   AND TEMP[17].x, TEMP[14].xxxx, TEMP[16].xxxx

Which is not the same when native integers are being used.

 src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 27e4615..b818139 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -1354,7 +1354,7 @@ glsl_to_tgsi_visitor::visit(ir_expression *ir)
 
    /* Quick peephole: Emit OPCODE_MAD(-a, -b, a) instead of AND(a, NOT(b))
     */
-   if (ir->operation == ir_binop_logic_and) {
+   if (!native_integers && ir->operation == ir_binop_logic_and) {
       if (try_emit_mad_for_and_not(ir, 1))
 	 return;
       if (try_emit_mad_for_and_not(ir, 0))
-- 
1.8.5.5