glsl: move to compiler/

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Matt Turner <mattst88@gmail.com>
Acked-by: Jose Fonseca <jfonseca@vmware.com>

1 files changed, 1061 insertions, 0 deletions

diff --git a/src/compiler/glsl/lower_instructions.cpp b/src/compiler/glsl/lower_instructions.cpp
new file mode 100644
index 0000000..1875149
--- /dev/null
+++ b/src/compiler/glsl/lower_instructions.cpp
@@ -0,0 +1,1061 @@
+/*
+ * Copyright © 2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file lower_instructions.cpp
+ *
+ * Many GPUs lack native instructions for certain expression operations, and
+ * must replace them with some other expression tree.  This pass lowers some
+ * of the most common cases, allowing the lowering code to be implemented once
+ * rather than in each driver backend.
+ *
+ * Currently supported transformations:
+ * - SUB_TO_ADD_NEG
+ * - DIV_TO_MUL_RCP
+ * - INT_DIV_TO_MUL_RCP
+ * - EXP_TO_EXP2
+ * - POW_TO_EXP2
+ * - LOG_TO_LOG2
+ * - MOD_TO_FLOOR
+ * - LDEXP_TO_ARITH
+ * - DFREXP_TO_ARITH
+ * - CARRY_TO_ARITH
+ * - BORROW_TO_ARITH
+ * - SAT_TO_CLAMP
+ * - DOPS_TO_DFRAC
+ *
+ * SUB_TO_ADD_NEG:
+ * ---------------
+ * Breaks an ir_binop_sub expression down to add(op0, neg(op1))
+ *
+ * This simplifies expression reassociation, and for many backends
+ * there is no subtract operation separate from adding the negation.
+ * For backends with native subtract operations, they will probably
+ * want to recognize add(op0, neg(op1)) or the other way around to
+ * produce a subtract anyway.
+ *
+ * DIV_TO_MUL_RCP and INT_DIV_TO_MUL_RCP:
+ * --------------------------------------
+ * Breaks an ir_binop_div expression down to op0 * (rcp(op1)).
+ *
+ * Many GPUs don't have a divide instruction (945 and 965 included),
+ * but they do have an RCP instruction to compute an approximate
+ * reciprocal.  By breaking the operation down, constant reciprocals
+ * can get constant folded.
+ *
+ * DIV_TO_MUL_RCP only lowers floating point division; INT_DIV_TO_MUL_RCP
+ * handles the integer case, converting to and from floating point so that
+ * RCP is possible.
+ *
+ * EXP_TO_EXP2 and LOG_TO_LOG2:
+ * ----------------------------
+ * Many GPUs don't have a base e log or exponent instruction, but they
+ * do have base 2 versions, so this pass converts exp and log to exp2
+ * and log2 operations.
+ *
+ * POW_TO_EXP2:
+ * -----------
+ * Many older GPUs don't have an x**y instruction.  For these GPUs, convert
+ * x**y to 2**(y * log2(x)).
+ *
+ * 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.
+ *
+ * Note: before we used to implement this as op1 * fract(op / op1) but this
+ * implementation had significant precision errors.
+ *
+ * LDEXP_TO_ARITH:
+ * -------------
+ * Converts ir_binop_ldexp to arithmetic and bit operations for float sources.
+ *
+ * DFREXP_DLDEXP_TO_ARITH:
+ * ---------------
+ * Converts ir_binop_ldexp, ir_unop_frexp_sig, and ir_unop_frexp_exp to
+ * arithmetic and bit ops for double arguments.
+ *
+ * CARRY_TO_ARITH:
+ * ---------------
+ * Converts ir_carry into (x + y) < x.
+ *
+ * BORROW_TO_ARITH:
+ * ----------------
+ * Converts ir_borrow into (x < y).
+ *
+ * SAT_TO_CLAMP:
+ * -------------
+ * Converts ir_unop_saturate into min(max(x, 0.0), 1.0)
+ *
+ * DOPS_TO_DFRAC:
+ * --------------
+ * Converts double trunc, ceil, floor, round to fract
+ */
+
+#include "c99_math.h"
+#include "program/prog_instruction.h" /* for swizzle */
+#include "compiler/glsl_types.h"
+#include "ir.h"
+#include "ir_builder.h"
+#include "ir_optimization.h"
+
+using namespace ir_builder;
+
+namespace {
+
+class lower_instructions_visitor : public ir_hierarchical_visitor {
+public:
+   lower_instructions_visitor(unsigned lower)
+      : progress(false), lower(lower) { }
+
+   ir_visitor_status visit_leave(ir_expression *);
+
+   bool progress;
+
+private:
+   unsigned lower; /** Bitfield of which operations to lower */
+
+   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 pow_to_exp2(ir_expression *);
+   void log_to_log2(ir_expression *);
+   void ldexp_to_arith(ir_expression *);
+   void dldexp_to_arith(ir_expression *);
+   void dfrexp_sig_to_arith(ir_expression *);
+   void dfrexp_exp_to_arith(ir_expression *);
+   void carry_to_arith(ir_expression *);
+   void borrow_to_arith(ir_expression *);
+   void sat_to_clamp(ir_expression *);
+   void double_dot_to_fma(ir_expression *);
+   void double_lrp(ir_expression *);
+   void dceil_to_dfrac(ir_expression *);
+   void dfloor_to_dfrac(ir_expression *);
+   void dround_even_to_dfrac(ir_expression *);
+   void dtrunc_to_dfrac(ir_expression *);
+   void dsign_to_csel(ir_expression *);
+};
+
+} /* anonymous namespace */
+
+/**
+ * Determine if a particular type of lowering should occur
+ */
+#define lowering(x) (this->lower & x)
+
+bool
+lower_instructions(exec_list *instructions, unsigned what_to_lower)
+{
+   lower_instructions_visitor v(what_to_lower);
+
+   visit_list_elements(&v, instructions);
+   return v.progress;
+}
+
+void
+lower_instructions_visitor::sub_to_add_neg(ir_expression *ir)
+{
+   ir->operation = ir_binop_add;
+   ir->operands[1] = new(ir) ir_expression(ir_unop_neg, ir->operands[1]->type,
+					   ir->operands[1], NULL);
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::div_to_mul_rcp(ir_expression *ir)
+{
+   assert(ir->operands[1]->type->is_float() || ir->operands[1]->type->is_double());
+
+   /* New expression for the 1.0 / op1 */
+   ir_rvalue *expr;
+   expr = new(ir) ir_expression(ir_unop_rcp,
+				ir->operands[1]->type,
+				ir->operands[1]);
+
+   /* op0 / op1 -> op0 * (1.0 / op1) */
+   ir->operation = ir_binop_mul;
+   ir->operands[1] = expr;
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::int_div_to_mul_rcp(ir_expression *ir)
+{
+   assert(ir->operands[1]->type->is_integer());
+
+   /* Be careful with integer division -- we need to do it as a
+    * float and re-truncate, since rcp(n > 1) of an integer would
+    * just be 0.
+    */
+   ir_rvalue *op0, *op1;
+   const struct glsl_type *vec_type;
+
+   vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
+				      ir->operands[1]->type->vector_elements,
+				      ir->operands[1]->type->matrix_columns);
+
+   if (ir->operands[1]->type->base_type == GLSL_TYPE_INT)
+      op1 = new(ir) ir_expression(ir_unop_i2f, vec_type, ir->operands[1], NULL);
+   else
+      op1 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[1], NULL);
+
+   op1 = new(ir) ir_expression(ir_unop_rcp, op1->type, op1, NULL);
+
+   vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
+				      ir->operands[0]->type->vector_elements,
+				      ir->operands[0]->type->matrix_columns);
+
+   if (ir->operands[0]->type->base_type == GLSL_TYPE_INT)
+      op0 = new(ir) ir_expression(ir_unop_i2f, vec_type, ir->operands[0], NULL);
+   else
+      op0 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[0], NULL);
+
+   vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
+				      ir->type->vector_elements,
+				      ir->type->matrix_columns);
+
+   op0 = new(ir) ir_expression(ir_binop_mul, vec_type, op0, op1);
+
+   if (ir->operands[1]->type->base_type == GLSL_TYPE_INT) {
+      ir->operation = ir_unop_f2i;
+      ir->operands[0] = op0;
+   } else {
+      ir->operation = ir_unop_i2u;
+      ir->operands[0] = new(ir) ir_expression(ir_unop_f2i, op0);
+   }
+   ir->operands[1] = NULL;
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::exp_to_exp2(ir_expression *ir)
+{
+   ir_constant *log2_e = new(ir) ir_constant(float(M_LOG2E));
+
+   ir->operation = ir_unop_exp2;
+   ir->operands[0] = new(ir) ir_expression(ir_binop_mul, ir->operands[0]->type,
+					   ir->operands[0], log2_e);
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::pow_to_exp2(ir_expression *ir)
+{
+   ir_expression *const log2_x =
+      new(ir) ir_expression(ir_unop_log2, ir->operands[0]->type,
+			    ir->operands[0]);
+
+   ir->operation = ir_unop_exp2;
+   ir->operands[0] = new(ir) ir_expression(ir_binop_mul, ir->operands[1]->type,
+					   ir->operands[1], log2_x);
+   ir->operands[1] = NULL;
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::log_to_log2(ir_expression *ir)
+{
+   ir->operation = ir_binop_mul;
+   ir->operands[0] = new(ir) ir_expression(ir_unop_log2, ir->operands[0]->type,
+					   ir->operands[0], NULL);
+   ir->operands[1] = new(ir) ir_constant(float(1.0 / M_LOG2E));
+   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], NULL);
+   ir_assignment *const assign_y =
+      new(ir) ir_assignment(new(ir) ir_dereference_variable(y),
+                            ir->operands[1], NULL);
+
+   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(DIV_TO_MUL_RCP) && (ir->type->is_float() || 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->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)
+{
+   /* Translates
+    *    ir_binop_ldexp x exp
+    * into
+    *
+    *    extracted_biased_exp = rshift(bitcast_f2i(abs(x)), exp_shift);
+    *    resulting_biased_exp = extracted_biased_exp + exp;
+    *
+    *    if (resulting_biased_exp < 1) {
+    *       return copysign(0.0, x);
+    *    }
+    *
+    *    return bitcast_u2f((bitcast_f2u(x) & sign_mantissa_mask) |
+    *                       lshift(i2u(resulting_biased_exp), exp_shift));
+    *
+    * which we can't actually implement as such, since the GLSL IR doesn't
+    * have vectorized if-statements. We actually implement it without branches
+    * using conditional-select:
+    *
+    *    extracted_biased_exp = rshift(bitcast_f2i(abs(x)), exp_shift);
+    *    resulting_biased_exp = extracted_biased_exp + exp;
+    *
+    *    is_not_zero_or_underflow = gequal(resulting_biased_exp, 1);
+    *    x = csel(is_not_zero_or_underflow, x, copysign(0.0f, x));
+    *    resulting_biased_exp = csel(is_not_zero_or_underflow,
+    *                                resulting_biased_exp, 0);
+    *
+    *    return bitcast_u2f((bitcast_f2u(x) & sign_mantissa_mask) |
+    *                       lshift(i2u(resulting_biased_exp), exp_shift));
+    */
+
+   const unsigned vec_elem = ir->type->vector_elements;
+
+   /* Types */
+   const glsl_type *ivec = glsl_type::get_instance(GLSL_TYPE_INT, vec_elem, 1);
+   const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
+
+   /* Constants */
+   ir_constant *zeroi = ir_constant::zero(ir, ivec);
+
+   ir_constant *sign_mask = new(ir) ir_constant(0x80000000u, vec_elem);
+
+   ir_constant *exp_shift = new(ir) ir_constant(23, vec_elem);
+   ir_constant *exp_width = new(ir) ir_constant(8, vec_elem);
+
+   /* Temporary variables */
+   ir_variable *x = new(ir) ir_variable(ir->type, "x", ir_var_temporary);
+   ir_variable *exp = new(ir) ir_variable(ivec, "exp", ir_var_temporary);
+
+   ir_variable *zero_sign_x = new(ir) ir_variable(ir->type, "zero_sign_x",
+                                                  ir_var_temporary);
+
+   ir_variable *extracted_biased_exp =
+      new(ir) ir_variable(ivec, "extracted_biased_exp", ir_var_temporary);
+   ir_variable *resulting_biased_exp =
+      new(ir) ir_variable(ivec, "resulting_biased_exp", ir_var_temporary);
+
+   ir_variable *is_not_zero_or_underflow =
+      new(ir) ir_variable(bvec, "is_not_zero_or_underflow", ir_var_temporary);
+
+   ir_instruction &i = *base_ir;
+
+   /* Copy <x> and <exp> arguments. */
+   i.insert_before(x);
+   i.insert_before(assign(x, ir->operands[0]));
+   i.insert_before(exp);
+   i.insert_before(assign(exp, ir->operands[1]));
+
+   /* Extract the biased exponent from <x>. */
+   i.insert_before(extracted_biased_exp);
+   i.insert_before(assign(extracted_biased_exp,
+                          rshift(bitcast_f2i(abs(x)), exp_shift)));
+
+   i.insert_before(resulting_biased_exp);
+   i.insert_before(assign(resulting_biased_exp,
+                          add(extracted_biased_exp, exp)));
+
+   /* Test if result is ±0.0, subnormal, or underflow by checking if the
+    * resulting biased exponent would be less than 0x1. If so, the result is
+    * 0.0 with the sign of x. (Actually, invert the conditions so that
+    * immediate values are the second arguments, which is better for i965)
+    */
+   i.insert_before(zero_sign_x);
+   i.insert_before(assign(zero_sign_x,
+                          bitcast_u2f(bit_and(bitcast_f2u(x), sign_mask))));
+
+   i.insert_before(is_not_zero_or_underflow);
+   i.insert_before(assign(is_not_zero_or_underflow,
+                          gequal(resulting_biased_exp,
+                                  new(ir) ir_constant(0x1, vec_elem))));
+   i.insert_before(assign(x, csel(is_not_zero_or_underflow,
+                                  x, zero_sign_x)));
+   i.insert_before(assign(resulting_biased_exp,
+                          csel(is_not_zero_or_underflow,
+                               resulting_biased_exp, zeroi)));
+
+   /* We could test for overflows by checking if the resulting biased exponent
+    * would be greater than 0xFE. Turns out we don't need to because the GLSL
+    * spec says:
+    *
+    *    "If this product is too large to be represented in the
+    *     floating-point type, the result is undefined."
+    */
+
+   ir_constant *exp_shift_clone = exp_shift->clone(ir, NULL);
+   ir->operation = ir_unop_bitcast_i2f;
+   ir->operands[0] = bitfield_insert(bitcast_f2i(x), resulting_biased_exp,
+                                     exp_shift_clone, exp_width);
+   ir->operands[1] = NULL;
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dldexp_to_arith(ir_expression *ir)
+{
+   /* See ldexp_to_arith for structure. Uses frexp_exp to extract the exponent
+    * from the significand.
+    */
+
+   const unsigned vec_elem = ir->type->vector_elements;
+
+   /* Types */
+   const glsl_type *ivec = glsl_type::get_instance(GLSL_TYPE_INT, vec_elem, 1);
+   const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
+
+   /* Constants */
+   ir_constant *zeroi = ir_constant::zero(ir, ivec);
+
+   ir_constant *sign_mask = new(ir) ir_constant(0x80000000u);
+
+   ir_constant *exp_shift = new(ir) ir_constant(20u);
+   ir_constant *exp_width = new(ir) ir_constant(11u);
+   ir_constant *exp_bias = new(ir) ir_constant(1022, vec_elem);
+
+   /* Temporary variables */
+   ir_variable *x = new(ir) ir_variable(ir->type, "x", ir_var_temporary);
+   ir_variable *exp = new(ir) ir_variable(ivec, "exp", ir_var_temporary);
+
+   ir_variable *zero_sign_x = new(ir) ir_variable(ir->type, "zero_sign_x",
+                                                  ir_var_temporary);
+
+   ir_variable *extracted_biased_exp =
+      new(ir) ir_variable(ivec, "extracted_biased_exp", ir_var_temporary);
+   ir_variable *resulting_biased_exp =
+      new(ir) ir_variable(ivec, "resulting_biased_exp", ir_var_temporary);
+
+   ir_variable *is_not_zero_or_underflow =
+      new(ir) ir_variable(bvec, "is_not_zero_or_underflow", ir_var_temporary);
+
+   ir_instruction &i = *base_ir;
+
+   /* Copy <x> and <exp> arguments. */
+   i.insert_before(x);
+   i.insert_before(assign(x, ir->operands[0]));
+   i.insert_before(exp);
+   i.insert_before(assign(exp, ir->operands[1]));
+
+   ir_expression *frexp_exp = expr(ir_unop_frexp_exp, x);
+   if (lowering(DFREXP_DLDEXP_TO_ARITH))
+      dfrexp_exp_to_arith(frexp_exp);
+
+   /* Extract the biased exponent from <x>. */
+   i.insert_before(extracted_biased_exp);
+   i.insert_before(assign(extracted_biased_exp, add(frexp_exp, exp_bias)));
+
+   i.insert_before(resulting_biased_exp);
+   i.insert_before(assign(resulting_biased_exp,
+                          add(extracted_biased_exp, exp)));
+
+   /* Test if result is ±0.0, subnormal, or underflow by checking if the
+    * resulting biased exponent would be less than 0x1. If so, the result is
+    * 0.0 with the sign of x. (Actually, invert the conditions so that
+    * immediate values are the second arguments, which is better for i965)
+    * TODO: Implement in a vector fashion.
+    */
+   i.insert_before(zero_sign_x);
+   for (unsigned elem = 0; elem < vec_elem; elem++) {
+      ir_variable *unpacked =
+         new(ir) ir_variable(glsl_type::uvec2_type, "unpacked", ir_var_temporary);
+      i.insert_before(unpacked);
+      i.insert_before(
+            assign(unpacked,
+                   expr(ir_unop_unpack_double_2x32, swizzle(x, elem, 1))));
+      i.insert_before(assign(unpacked, bit_and(swizzle_y(unpacked), sign_mask->clone(ir, NULL)),
+                             WRITEMASK_Y));
+      i.insert_before(assign(unpacked, ir_constant::zero(ir, glsl_type::uint_type), WRITEMASK_X));
+      i.insert_before(assign(zero_sign_x,
+                             expr(ir_unop_pack_double_2x32, unpacked),
+                             1 << elem));
+   }
+   i.insert_before(is_not_zero_or_underflow);
+   i.insert_before(assign(is_not_zero_or_underflow,
+                          gequal(resulting_biased_exp,
+                                  new(ir) ir_constant(0x1, vec_elem))));
+   i.insert_before(assign(x, csel(is_not_zero_or_underflow,
+                                  x, zero_sign_x)));
+   i.insert_before(assign(resulting_biased_exp,
+                          csel(is_not_zero_or_underflow,
+                               resulting_biased_exp, zeroi)));
+
+   /* We could test for overflows by checking if the resulting biased exponent
+    * would be greater than 0xFE. Turns out we don't need to because the GLSL
+    * spec says:
+    *
+    *    "If this product is too large to be represented in the
+    *     floating-point type, the result is undefined."
+    */
+
+   ir_rvalue *results[4] = {NULL};
+   for (unsigned elem = 0; elem < vec_elem; elem++) {
+      ir_variable *unpacked =
+         new(ir) ir_variable(glsl_type::uvec2_type, "unpacked", ir_var_temporary);
+      i.insert_before(unpacked);
+      i.insert_before(
+            assign(unpacked,
+                   expr(ir_unop_unpack_double_2x32, swizzle(x, elem, 1))));
+
+      ir_expression *bfi = bitfield_insert(
+            swizzle_y(unpacked),
+            i2u(swizzle(resulting_biased_exp, elem, 1)),
+            exp_shift->clone(ir, NULL),
+            exp_width->clone(ir, NULL));
+
+      i.insert_before(assign(unpacked, bfi, WRITEMASK_Y));
+
+      results[elem] = expr(ir_unop_pack_double_2x32, unpacked);
+   }
+
+   ir->operation = ir_quadop_vector;
+   ir->operands[0] = results[0];
+   ir->operands[1] = results[1];
+   ir->operands[2] = results[2];
+   ir->operands[3] = results[3];
+
+   /* Don't generate new IR that would need to be lowered in an additional
+    * pass.
+    */
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dfrexp_sig_to_arith(ir_expression *ir)
+{
+   const unsigned vec_elem = ir->type->vector_elements;
+   const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
+
+   /* Double-precision floating-point values are stored as
+    *   1 sign bit;
+    *   11 exponent bits;
+    *   52 mantissa bits.
+    *
+    * We're just extracting the significand here, so we only need to modify
+    * the upper 32-bit uint. Unfortunately we must extract each double
+    * independently as there is no vector version of unpackDouble.
+    */
+
+   ir_instruction &i = *base_ir;
+
+   ir_variable *is_not_zero =
+      new(ir) ir_variable(bvec, "is_not_zero", ir_var_temporary);
+   ir_rvalue *results[4] = {NULL};
+
+   ir_constant *dzero = new(ir) ir_constant(0.0, vec_elem);
+   i.insert_before(is_not_zero);
+   i.insert_before(
+         assign(is_not_zero,
+                nequal(abs(ir->operands[0]->clone(ir, NULL)), dzero)));
+
+   /* TODO: Remake this as more vector-friendly when int64 support is
+    * available.
+    */
+   for (unsigned elem = 0; elem < vec_elem; elem++) {
+      ir_constant *zero = new(ir) ir_constant(0u, 1);
+      ir_constant *sign_mantissa_mask = new(ir) ir_constant(0x800fffffu, 1);
+
+      /* Exponent of double floating-point values in the range [0.5, 1.0). */
+      ir_constant *exponent_value = new(ir) ir_constant(0x3fe00000u, 1);
+
+      ir_variable *bits =
+         new(ir) ir_variable(glsl_type::uint_type, "bits", ir_var_temporary);
+      ir_variable *unpacked =
+         new(ir) ir_variable(glsl_type::uvec2_type, "unpacked", ir_var_temporary);
+
+      ir_rvalue *x = swizzle(ir->operands[0]->clone(ir, NULL), elem, 1);
+
+      i.insert_before(bits);
+      i.insert_before(unpacked);
+      i.insert_before(assign(unpacked, expr(ir_unop_unpack_double_2x32, x)));
+
+      /* Manipulate the high uint to remove the exponent and replace it with
+       * either the default exponent or zero.
+       */
+      i.insert_before(assign(bits, swizzle_y(unpacked)));
+      i.insert_before(assign(bits, bit_and(bits, sign_mantissa_mask)));
+      i.insert_before(assign(bits, bit_or(bits,
+                                          csel(swizzle(is_not_zero, elem, 1),
+                                               exponent_value,
+                                               zero))));
+      i.insert_before(assign(unpacked, bits, WRITEMASK_Y));
+      results[elem] = expr(ir_unop_pack_double_2x32, unpacked);
+   }
+
+   /* Put the dvec back together */
+   ir->operation = ir_quadop_vector;
+   ir->operands[0] = results[0];
+   ir->operands[1] = results[1];
+   ir->operands[2] = results[2];
+   ir->operands[3] = results[3];
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dfrexp_exp_to_arith(ir_expression *ir)
+{
+   const unsigned vec_elem = ir->type->vector_elements;
+   const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
+   const glsl_type *uvec = glsl_type::get_instance(GLSL_TYPE_UINT, vec_elem, 1);
+
+   /* Double-precision floating-point values are stored as
+    *   1 sign bit;
+    *   11 exponent bits;
+    *   52 mantissa bits.
+    *
+    * We're just extracting the exponent here, so we only care about the upper
+    * 32-bit uint.
+    */
+
+   ir_instruction &i = *base_ir;
+
+   ir_variable *is_not_zero =
+      new(ir) ir_variable(bvec, "is_not_zero", ir_var_temporary);
+   ir_variable *high_words =
+      new(ir) ir_variable(uvec, "high_words", ir_var_temporary);
+   ir_constant *dzero = new(ir) ir_constant(0.0, vec_elem);
+   ir_constant *izero = new(ir) ir_constant(0, vec_elem);
+
+   ir_rvalue *absval = abs(ir->operands[0]);
+
+   i.insert_before(is_not_zero);
+   i.insert_before(high_words);
+   i.insert_before(assign(is_not_zero, nequal(absval->clone(ir, NULL), dzero)));
+
+   /* Extract all of the upper uints. */
+   for (unsigned elem = 0; elem < vec_elem; elem++) {
+      ir_rvalue *x = swizzle(absval->clone(ir, NULL), elem, 1);
+
+      i.insert_before(assign(high_words,
+                             swizzle_y(expr(ir_unop_unpack_double_2x32, x)),
+                             1 << elem));
+
+   }
+   ir_constant *exponent_shift = new(ir) ir_constant(20, vec_elem);
+   ir_constant *exponent_bias = new(ir) ir_constant(-1022, vec_elem);
+
+   /* For non-zero inputs, shift the exponent down and apply bias. */
+   ir->operation = ir_triop_csel;
+   ir->operands[0] = new(ir) ir_dereference_variable(is_not_zero);
+   ir->operands[1] = add(exponent_bias, u2i(rshift(high_words, exponent_shift)));
+   ir->operands[2] = izero;
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::carry_to_arith(ir_expression *ir)
+{
+   /* Translates
+    *   ir_binop_carry x y
+    * into
+    *   sum = ir_binop_add x y
+    *   bcarry = ir_binop_less sum x
+    *   carry = ir_unop_b2i bcarry
+    */
+
+   ir_rvalue *x_clone = ir->operands[0]->clone(ir, NULL);
+   ir->operation = ir_unop_i2u;
+   ir->operands[0] = b2i(less(add(ir->operands[0], ir->operands[1]), x_clone));
+   ir->operands[1] = NULL;
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::borrow_to_arith(ir_expression *ir)
+{
+   /* Translates
+    *   ir_binop_borrow x y
+    * into
+    *   bcarry = ir_binop_less x y
+    *   carry = ir_unop_b2i bcarry
+    */
+
+   ir->operation = ir_unop_i2u;
+   ir->operands[0] = b2i(less(ir->operands[0], ir->operands[1]));
+   ir->operands[1] = NULL;
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::sat_to_clamp(ir_expression *ir)
+{
+   /* Translates
+    *   ir_unop_saturate x
+    * into
+    *   ir_binop_min (ir_binop_max(x, 0.0), 1.0)
+    */
+
+   ir->operation = ir_binop_min;
+   ir->operands[0] = new(ir) ir_expression(ir_binop_max, ir->operands[0]->type,
+                                           ir->operands[0],
+                                           new(ir) ir_constant(0.0f));
+   ir->operands[1] = new(ir) ir_constant(1.0f);
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::double_dot_to_fma(ir_expression *ir)
+{
+   ir_variable *temp = new(ir) ir_variable(ir->operands[0]->type->get_base_type(), "dot_res",
+					   ir_var_temporary);
+   this->base_ir->insert_before(temp);
+
+   int nc = ir->operands[0]->type->components();
+   for (int i = nc - 1; i >= 1; i--) {
+      ir_assignment *assig;
+      if (i == (nc - 1)) {
+         assig = assign(temp, mul(swizzle(ir->operands[0]->clone(ir, NULL), i, 1),
+                                  swizzle(ir->operands[1]->clone(ir, NULL), i, 1)));
+      } else {
+         assig = assign(temp, fma(swizzle(ir->operands[0]->clone(ir, NULL), i, 1),
+                                  swizzle(ir->operands[1]->clone(ir, NULL), i, 1),
+                                  temp));
+      }
+      this->base_ir->insert_before(assig);
+   }
+
+   ir->operation = ir_triop_fma;
+   ir->operands[0] = swizzle(ir->operands[0], 0, 1);
+   ir->operands[1] = swizzle(ir->operands[1], 0, 1);
+   ir->operands[2] = new(ir) ir_dereference_variable(temp);
+
+   this->progress = true;
+
+}
+
+void
+lower_instructions_visitor::double_lrp(ir_expression *ir)
+{
+   int swizval;
+   ir_rvalue *op0 = ir->operands[0], *op2 = ir->operands[2];
+   ir_constant *one = new(ir) ir_constant(1.0, op2->type->vector_elements);
+
+   switch (op2->type->vector_elements) {
+   case 1:
+      swizval = SWIZZLE_XXXX;
+      break;
+   default:
+      assert(op0->type->vector_elements == op2->type->vector_elements);
+      swizval = SWIZZLE_XYZW;
+      break;
+   }
+
+   ir->operation = ir_triop_fma;
+   ir->operands[0] = swizzle(op2, swizval, op0->type->vector_elements);
+   ir->operands[2] = mul(sub(one, op2->clone(ir, NULL)), op0);
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dceil_to_dfrac(ir_expression *ir)
+{
+   /*
+    * frtemp = frac(x);
+    * temp = sub(x, frtemp);
+    * result = temp + ((frtemp != 0.0) ? 1.0 : 0.0);
+    */
+   ir_instruction &i = *base_ir;
+   ir_constant *zero = new(ir) ir_constant(0.0, ir->operands[0]->type->vector_elements);
+   ir_constant *one = new(ir) ir_constant(1.0, ir->operands[0]->type->vector_elements);
+   ir_variable *frtemp = new(ir) ir_variable(ir->operands[0]->type, "frtemp",
+                                             ir_var_temporary);
+
+   i.insert_before(frtemp);
+   i.insert_before(assign(frtemp, fract(ir->operands[0])));
+
+   ir->operation = ir_binop_add;
+   ir->operands[0] = sub(ir->operands[0]->clone(ir, NULL), frtemp);
+   ir->operands[1] = csel(nequal(frtemp, zero), one, zero->clone(ir, NULL));
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dfloor_to_dfrac(ir_expression *ir)
+{
+   /*
+    * frtemp = frac(x);
+    * result = sub(x, frtemp);
+    */
+   ir->operation = ir_binop_sub;
+   ir->operands[1] = fract(ir->operands[0]->clone(ir, NULL));
+
+   this->progress = true;
+}
+void
+lower_instructions_visitor::dround_even_to_dfrac(ir_expression *ir)
+{
+   /*
+    * insane but works
+    * temp = x + 0.5;
+    * frtemp = frac(temp);
+    * t2 = sub(temp, frtemp);
+    * if (frac(x) == 0.5)
+    *     result = frac(t2 * 0.5) == 0 ? t2 : t2 - 1;
+    *  else
+    *     result = t2;
+
+    */
+   ir_instruction &i = *base_ir;
+   ir_variable *frtemp = new(ir) ir_variable(ir->operands[0]->type, "frtemp",
+                                             ir_var_temporary);
+   ir_variable *temp = new(ir) ir_variable(ir->operands[0]->type, "temp",
+                                           ir_var_temporary);
+   ir_variable *t2 = new(ir) ir_variable(ir->operands[0]->type, "t2",
+                                           ir_var_temporary);
+   ir_constant *p5 = new(ir) ir_constant(0.5, ir->operands[0]->type->vector_elements);
+   ir_constant *one = new(ir) ir_constant(1.0, ir->operands[0]->type->vector_elements);
+   ir_constant *zero = new(ir) ir_constant(0.0, ir->operands[0]->type->vector_elements);
+
+   i.insert_before(temp);
+   i.insert_before(assign(temp, add(ir->operands[0], p5)));
+
+   i.insert_before(frtemp);
+   i.insert_before(assign(frtemp, fract(temp)));
+
+   i.insert_before(t2);
+   i.insert_before(assign(t2, sub(temp, frtemp)));
+
+   ir->operation = ir_triop_csel;
+   ir->operands[0] = equal(fract(ir->operands[0]->clone(ir, NULL)),
+                           p5->clone(ir, NULL));
+   ir->operands[1] = csel(equal(fract(mul(t2, p5->clone(ir, NULL))),
+                                zero),
+                          t2,
+                          sub(t2, one));
+   ir->operands[2] = new(ir) ir_dereference_variable(t2);
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dtrunc_to_dfrac(ir_expression *ir)
+{
+   /*
+    * frtemp = frac(x);
+    * temp = sub(x, frtemp);
+    * result = x >= 0 ? temp : temp + (frtemp == 0.0) ? 0 : 1;
+    */
+   ir_rvalue *arg = ir->operands[0];
+   ir_instruction &i = *base_ir;
+
+   ir_constant *zero = new(ir) ir_constant(0.0, arg->type->vector_elements);
+   ir_constant *one = new(ir) ir_constant(1.0, arg->type->vector_elements);
+   ir_variable *frtemp = new(ir) ir_variable(arg->type, "frtemp",
+                                             ir_var_temporary);
+   ir_variable *temp = new(ir) ir_variable(ir->operands[0]->type, "temp",
+                                           ir_var_temporary);
+
+   i.insert_before(frtemp);
+   i.insert_before(assign(frtemp, fract(arg)));
+   i.insert_before(temp);
+   i.insert_before(assign(temp, sub(arg->clone(ir, NULL), frtemp)));
+
+   ir->operation = ir_triop_csel;
+   ir->operands[0] = gequal(arg->clone(ir, NULL), zero);
+   ir->operands[1] = new (ir) ir_dereference_variable(temp);
+   ir->operands[2] = add(temp,
+                         csel(equal(frtemp, zero->clone(ir, NULL)),
+                              zero->clone(ir, NULL),
+                              one));
+
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::dsign_to_csel(ir_expression *ir)
+{
+   /*
+    * temp = x > 0.0 ? 1.0 : 0.0;
+    * result = x < 0.0 ? -1.0 : temp;
+    */
+   ir_rvalue *arg = ir->operands[0];
+   ir_constant *zero = new(ir) ir_constant(0.0, arg->type->vector_elements);
+   ir_constant *one = new(ir) ir_constant(1.0, arg->type->vector_elements);
+   ir_constant *neg_one = new(ir) ir_constant(-1.0, arg->type->vector_elements);
+
+   ir->operation = ir_triop_csel;
+   ir->operands[0] = less(arg->clone(ir, NULL),
+                          zero->clone(ir, NULL));
+   ir->operands[1] = neg_one;
+   ir->operands[2] = csel(greater(arg, zero),
+                          one,
+                          zero->clone(ir, NULL));
+
+   this->progress = true;
+}
+
+ir_visitor_status
+lower_instructions_visitor::visit_leave(ir_expression *ir)
+{
+   switch (ir->operation) {
+   case ir_binop_dot:
+      if (ir->operands[0]->type->is_double())
+         double_dot_to_fma(ir);
+      break;
+   case ir_triop_lrp:
+      if (ir->operands[0]->type->is_double())
+         double_lrp(ir);
+      break;
+   case ir_binop_sub:
+      if (lowering(SUB_TO_ADD_NEG))
+	 sub_to_add_neg(ir);
+      break;
+
+   case ir_binop_div:
+      if (ir->operands[1]->type->is_integer() && lowering(INT_DIV_TO_MUL_RCP))
+	 int_div_to_mul_rcp(ir);
+      else if ((ir->operands[1]->type->is_float() ||
+                ir->operands[1]->type->is_double()) && lowering(DIV_TO_MUL_RCP))
+	 div_to_mul_rcp(ir);
+      break;
+
+   case ir_unop_exp:
+      if (lowering(EXP_TO_EXP2))
+	 exp_to_exp2(ir);
+      break;
+
+   case ir_unop_log:
+      if (lowering(LOG_TO_LOG2))
+	 log_to_log2(ir);
+      break;
+
+   case ir_binop_mod:
+      if (lowering(MOD_TO_FLOOR) && (ir->type->is_float() || ir->type->is_double()))
+	 mod_to_floor(ir);
+      break;
+
+   case ir_binop_pow:
+      if (lowering(POW_TO_EXP2))
+	 pow_to_exp2(ir);
+      break;
+
+   case ir_binop_ldexp:
+      if (lowering(LDEXP_TO_ARITH) && ir->type->is_float())
+         ldexp_to_arith(ir);
+      if (lowering(DFREXP_DLDEXP_TO_ARITH) && ir->type->is_double())
+         dldexp_to_arith(ir);
+      break;
+
+   case ir_unop_frexp_exp:
+      if (lowering(DFREXP_DLDEXP_TO_ARITH) && ir->operands[0]->type->is_double())
+         dfrexp_exp_to_arith(ir);
+      break;
+
+   case ir_unop_frexp_sig:
+      if (lowering(DFREXP_DLDEXP_TO_ARITH) && ir->operands[0]->type->is_double())
+         dfrexp_sig_to_arith(ir);
+      break;
+
+   case ir_binop_carry:
+      if (lowering(CARRY_TO_ARITH))
+         carry_to_arith(ir);
+      break;
+
+   case ir_binop_borrow:
+      if (lowering(BORROW_TO_ARITH))
+         borrow_to_arith(ir);
+      break;
+
+   case ir_unop_saturate:
+      if (lowering(SAT_TO_CLAMP))
+         sat_to_clamp(ir);
+      break;
+
+   case ir_unop_trunc:
+      if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
+         dtrunc_to_dfrac(ir);
+      break;
+
+   case ir_unop_ceil:
+      if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
+         dceil_to_dfrac(ir);
+      break;
+
+   case ir_unop_floor:
+      if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
+         dfloor_to_dfrac(ir);
+      break;
+
+   case ir_unop_round_even:
+      if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
+         dround_even_to_dfrac(ir);
+      break;
+
+   case ir_unop_sign:
+      if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
+         dsign_to_csel(ir);
+      break;
+   default:
+      return visit_continue;
+   }
+
+   return visit_continue;
+}