nir: improvements to native_integers removal

Improvements related to the patch that removed native_integers:
 * In glsl_to_nir, special cases for i2f,u2f,etc are no longer needed
 * In prog_to_nir, use sge/slt and let lower_scmp lower it if needed

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/glsl/glsl_to_nir.cpp

@@ -1877,20 +1877,10 @@ nir_visitor::visit(ir_expression *ir)
    case ir_unop_exp2: result = nir_fexp2(&b, srcs[0]); break;
    case ir_unop_log2: result = nir_flog2(&b, srcs[0]); break;
    case ir_unop_i2f:
-      result = nir_i2f32(&b, srcs[0]);
-      break;
    case ir_unop_u2f:
-      result = nir_u2f32(&b, srcs[0]);
-      break;
    case ir_unop_b2f:
-      result = nir_b2f32(&b, srcs[0]);
-      break;
    case ir_unop_f2i:
-      result = nir_f2i32(&b, srcs[0]);
-      break;
    case ir_unop_f2u:
-      result = nir_f2u32(&b, srcs[0]);
-      break;
    case ir_unop_f2b:
    case ir_unop_i2b:
    case ir_unop_b2i:

src/mesa/program/prog_to_nir.c

@@ -388,22 +388,16 @@ ptn_scs(nir_builder *b, nir_alu_dest dest, nir_ssa_def **src)
    ptn_move_dest_masked(b, dest, nir_imm_float(b, 1.0), WRITEMASK_W);
 }
 
-/**
- * Emit SLT.  For platforms with integers, prefer b2f(flt(...)).
- */
 static void
 ptn_slt(nir_builder *b, nir_alu_dest dest, nir_ssa_def **src)
 {
-   ptn_move_dest(b, dest, nir_b2f32(b, nir_flt(b, src[0], src[1])));
+   ptn_move_dest(b, dest, nir_slt(b, src[0], src[1]));
 }
 
-/**
- * Emit SGE.  For platforms with integers, prefer b2f(fge(...)).
- */
 static void
 ptn_sge(nir_builder *b, nir_alu_dest dest, nir_ssa_def **src)
 {
-   ptn_move_dest(b, dest, nir_b2f32(b, nir_fge(b, src[0], src[1])));
+   ptn_move_dest(b, dest, nir_sge(b, src[0], src[1]));
 }
 
 static void