i965/fs: Skip emitting MACH/MOV for small integers.

[mesa.git] / src / mesa / drivers / dri / i965 / brw_fs_visitor.cpp

diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index ce6d3dad1e59b9a8b783274d5c7c8934f5513452..c89f4d6a05ddc21081b2b8407de047e4affc2799 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -458,18 +458,27 @@ fs_visitor::visit(ir_expression *ir)
          * of one of the operands (src0 on gen6, src1 on gen7).  The
          * MACH accumulates in the contribution of the upper 16 bits
          * of that operand.
-         *
-         * FINISHME: Emit just the MUL if we know an operand is small
-         * enough.
-         */
-        if (brw->gen >= 7)
-           no16("SIMD16 explicit accumulator operands unsupported\n");
-
-        struct brw_reg acc = retype(brw_acc_reg(), this->result.type);
-
-        emit(MUL(acc, op[0], op[1]));
-        emit(MACH(reg_null_d, op[0], op[1]));
-        emit(MOV(this->result, fs_reg(acc)));
+          */
+         if (ir->operands[0]->is_uint16_constant()) {
+            if (brw->gen < 7)
+               emit(MUL(this->result, op[0], op[1]));
+            else
+               emit(MUL(this->result, op[1], op[0]));
+         } else if (ir->operands[1]->is_uint16_constant()) {
+            if (brw->gen < 7)
+               emit(MUL(this->result, op[1], op[0]));
+            else
+               emit(MUL(this->result, op[0], op[1]));
+         } else {
+            if (brw->gen >= 7)
+               no16("SIMD16 explicit accumulator operands unsupported\n");
+
+            struct brw_reg acc = retype(brw_acc_reg(), this->result.type);
+
+            emit(MUL(acc, op[0], op[1]));
+            emit(MACH(reg_null_d, op[0], op[1]));
+            emit(MOV(this->result, fs_reg(acc)));
+         }
       } else {
         emit(MUL(this->result, op[0], op[1]));
       }