glsl: Drop the dead MOD_TO_FLOOR path.

It's now called lower_fmod in NIR.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8044>

src/compiler/glsl/ir_optimization.h

@@ -38,7 +38,6 @@ struct gl_shader_program;
 #define FDIV_TO_MUL_RCP    0x02
 #define EXP_TO_EXP2        0x04
 #define LOG_TO_LOG2        0x10
-#define MOD_TO_FLOOR       0x20
 #define INT_DIV_TO_MUL_RCP 0x40
 #define LDEXP_TO_ARITH     0x80
 #define CARRY_TO_ARITH     0x100

src/compiler/glsl/lower_instructions.cpp

@@ -35,7 +35,6 @@
  * - INT_DIV_TO_MUL_RCP
  * - EXP_TO_EXP2
  * - LOG_TO_LOG2
- * - MOD_TO_FLOOR
  * - LDEXP_TO_ARITH
  * - CARRY_TO_ARITH
  * - BORROW_TO_ARITH
@@ -74,10 +73,6 @@
  * do have base 2 versions, so this pass converts exp and log to exp2
  * and log2 operations.
  *
- * MOD_TO_FLOOR:
- * -------------
- * Breaks an ir_binop_mod expression down to (op0 - op1 * floor(op0 / op1))
- *
  * Many GPUs don't have a MOD instruction (945 and 965 included), and
  * if we have to break it down like this anyway, it gives an
  * opportunity to do things like constant fold the (1.0 / op1) easily.
@@ -138,7 +133,6 @@ private:
    void sub_to_add_neg(ir_expression *);
    void div_to_mul_rcp(ir_expression *);
    void int_div_to_mul_rcp(ir_expression *);
-   void mod_to_floor(ir_expression *);
    void exp_to_exp2(ir_expression *);
    void log_to_log2(ir_expression *);
    void ldexp_to_arith(ir_expression *);
@@ -292,56 +286,6 @@ lower_instructions_visitor::log_to_log2(ir_expression *ir)
    this->progress = true;
 }
 
-void
-lower_instructions_visitor::mod_to_floor(ir_expression *ir)
-{
-   ir_variable *x = new(ir) ir_variable(ir->operands[0]->type, "mod_x",
-                                         ir_var_temporary);
-   ir_variable *y = new(ir) ir_variable(ir->operands[1]->type, "mod_y",
-                                         ir_var_temporary);
-   this->base_ir->insert_before(x);
-   this->base_ir->insert_before(y);
-
-   ir_assignment *const assign_x =
-      new(ir) ir_assignment(new(ir) ir_dereference_variable(x),
-                            ir->operands[0]);
-   ir_assignment *const assign_y =
-      new(ir) ir_assignment(new(ir) ir_dereference_variable(y),
-                            ir->operands[1]);
-
-   this->base_ir->insert_before(assign_x);
-   this->base_ir->insert_before(assign_y);
-
-   ir_expression *const div_expr =
-      new(ir) ir_expression(ir_binop_div, x->type,
-                            new(ir) ir_dereference_variable(x),
-                            new(ir) ir_dereference_variable(y));
-
-   /* Don't generate new IR that would need to be lowered in an additional
-    * pass.
-    */
-   if ((lowering(FDIV_TO_MUL_RCP) && ir->type->is_float_16_32()) ||
-       (lowering(DDIV_TO_MUL_RCP) && ir->type->is_double()))
-      div_to_mul_rcp(div_expr);
-
-   ir_expression *const floor_expr =
-      new(ir) ir_expression(ir_unop_floor, x->type, div_expr);
-
-   if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
-      dfloor_to_dfrac(floor_expr);
-
-   ir_expression *const mul_expr =
-      new(ir) ir_expression(ir_binop_mul,
-                            new(ir) ir_dereference_variable(y),
-                            floor_expr);
-
-   ir->operation = ir_binop_sub;
-   ir->init_num_operands();
-   ir->operands[0] = new(ir) ir_dereference_variable(x);
-   ir->operands[1] = mul_expr;
-   this->progress = true;
-}
-
 void
 lower_instructions_visitor::ldexp_to_arith(ir_expression *ir)
 {
@@ -1766,11 +1710,6 @@ lower_instructions_visitor::visit_leave(ir_expression *ir)
 	 log_to_log2(ir);
       break;
 
-   case ir_binop_mod:
-      if (lowering(MOD_TO_FLOOR) && ir->type->is_float_16_32_64())
-	 mod_to_floor(ir);
-      break;
-
    case ir_binop_ldexp:
       if (lowering(LDEXP_TO_ARITH) && ir->type->is_float())
          ldexp_to_arith(ir);

src/intel/compiler/brw_vec4_nir.cpp

@@ -1900,7 +1900,7 @@ vec4_visitor::nir_emit_alu(nir_alu_instr *instr)
       unreachable("not reached: should be lowered by DIV_TO_MUL_RCP in the compiler");
 
    case nir_op_fmod:
-      unreachable("not reached: should be lowered by MOD_TO_FLOOR in the compiler");
+      unreachable("not reached: should be lowered by lower_fmod in the compiler");
 
    case nir_op_fsub:
    case nir_op_isub: