glsl: move to compiler/
[mesa.git] / src / compiler / glsl / opt_algebraic.cpp
diff --git a/src/compiler/glsl/opt_algebraic.cpp b/src/compiler/glsl/opt_algebraic.cpp
new file mode 100644 (file)
index 0000000..1e58062
--- /dev/null
@@ -0,0 +1,984 @@
+/*
+ * 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 opt_algebraic.cpp
+ *
+ * Takes advantage of association, commutivity, and other algebraic
+ * properties to simplify expressions.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_rvalue_visitor.h"
+#include "ir_optimization.h"
+#include "ir_builder.h"
+#include "compiler/glsl_types.h"
+
+using namespace ir_builder;
+
+namespace {
+
+/**
+ * Visitor class for replacing expressions with ir_constant values.
+ */
+
+class ir_algebraic_visitor : public ir_rvalue_visitor {
+public:
+   ir_algebraic_visitor(bool native_integers,
+                        const struct gl_shader_compiler_options *options)
+      : options(options)
+   {
+      this->progress = false;
+      this->mem_ctx = NULL;
+      this->native_integers = native_integers;
+   }
+
+   virtual ~ir_algebraic_visitor()
+   {
+   }
+
+   ir_rvalue *handle_expression(ir_expression *ir);
+   void handle_rvalue(ir_rvalue **rvalue);
+   bool reassociate_constant(ir_expression *ir1,
+                            int const_index,
+                            ir_constant *constant,
+                            ir_expression *ir2);
+   void reassociate_operands(ir_expression *ir1,
+                            int op1,
+                            ir_expression *ir2,
+                            int op2);
+   ir_rvalue *swizzle_if_required(ir_expression *expr,
+                                 ir_rvalue *operand);
+
+   const struct gl_shader_compiler_options *options;
+   void *mem_ctx;
+
+   bool native_integers;
+   bool progress;
+};
+
+} /* unnamed namespace */
+
+static inline bool
+is_vec_zero(ir_constant *ir)
+{
+   return (ir == NULL) ? false : ir->is_zero();
+}
+
+static inline bool
+is_vec_one(ir_constant *ir)
+{
+   return (ir == NULL) ? false : ir->is_one();
+}
+
+static inline bool
+is_vec_two(ir_constant *ir)
+{
+   return (ir == NULL) ? false : ir->is_value(2.0, 2);
+}
+
+static inline bool
+is_vec_four(ir_constant *ir)
+{
+   return (ir == NULL) ? false : ir->is_value(4.0, 4);
+}
+
+static inline bool
+is_vec_negative_one(ir_constant *ir)
+{
+   return (ir == NULL) ? false : ir->is_negative_one();
+}
+
+static inline bool
+is_valid_vec_const(ir_constant *ir)
+{
+   if (ir == NULL)
+      return false;
+
+   if (!ir->type->is_scalar() && !ir->type->is_vector())
+      return false;
+
+   return true;
+}
+
+static inline bool
+is_less_than_one(ir_constant *ir)
+{
+   assert(ir->type->base_type == GLSL_TYPE_FLOAT);
+
+   if (!is_valid_vec_const(ir))
+      return false;
+
+   unsigned component = 0;
+   for (int c = 0; c < ir->type->vector_elements; c++) {
+      if (ir->get_float_component(c) < 1.0f)
+         component++;
+   }
+
+   return (component == ir->type->vector_elements);
+}
+
+static inline bool
+is_greater_than_zero(ir_constant *ir)
+{
+   assert(ir->type->base_type == GLSL_TYPE_FLOAT);
+
+   if (!is_valid_vec_const(ir))
+      return false;
+
+   unsigned component = 0;
+   for (int c = 0; c < ir->type->vector_elements; c++) {
+      if (ir->get_float_component(c) > 0.0f)
+         component++;
+   }
+
+   return (component == ir->type->vector_elements);
+}
+
+static void
+update_type(ir_expression *ir)
+{
+   if (ir->operands[0]->type->is_vector())
+      ir->type = ir->operands[0]->type;
+   else
+      ir->type = ir->operands[1]->type;
+}
+
+/* Recognize (v.x + v.y) + (v.z + v.w) as dot(v, 1.0) */
+static ir_expression *
+try_replace_with_dot(ir_expression *expr0, ir_expression *expr1, void *mem_ctx)
+{
+   if (expr0 && expr0->operation == ir_binop_add &&
+       expr0->type->is_float() &&
+       expr1 && expr1->operation == ir_binop_add &&
+       expr1->type->is_float()) {
+      ir_swizzle *x = expr0->operands[0]->as_swizzle();
+      ir_swizzle *y = expr0->operands[1]->as_swizzle();
+      ir_swizzle *z = expr1->operands[0]->as_swizzle();
+      ir_swizzle *w = expr1->operands[1]->as_swizzle();
+
+      if (!x || x->mask.num_components != 1 ||
+          !y || y->mask.num_components != 1 ||
+          !z || z->mask.num_components != 1 ||
+          !w || w->mask.num_components != 1) {
+         return NULL;
+      }
+
+      bool swiz_seen[4] = {false, false, false, false};
+      swiz_seen[x->mask.x] = true;
+      swiz_seen[y->mask.x] = true;
+      swiz_seen[z->mask.x] = true;
+      swiz_seen[w->mask.x] = true;
+
+      if (!swiz_seen[0] || !swiz_seen[1] ||
+          !swiz_seen[2] || !swiz_seen[3]) {
+         return NULL;
+      }
+
+      if (x->val->equals(y->val) &&
+          x->val->equals(z->val) &&
+          x->val->equals(w->val)) {
+         return dot(x->val, new(mem_ctx) ir_constant(1.0f, 4));
+      }
+   }
+   return NULL;
+}
+
+void
+ir_algebraic_visitor::reassociate_operands(ir_expression *ir1,
+                                          int op1,
+                                          ir_expression *ir2,
+                                          int op2)
+{
+   ir_rvalue *temp = ir2->operands[op2];
+   ir2->operands[op2] = ir1->operands[op1];
+   ir1->operands[op1] = temp;
+
+   /* Update the type of ir2.  The type of ir1 won't have changed --
+    * base types matched, and at least one of the operands of the 2
+    * binops is still a vector if any of them were.
+    */
+   update_type(ir2);
+
+   this->progress = true;
+}
+
+/**
+ * Reassociates a constant down a tree of adds or multiplies.
+ *
+ * Consider (2 * (a * (b * 0.5))).  We want to send up with a * b.
+ */
+bool
+ir_algebraic_visitor::reassociate_constant(ir_expression *ir1, int const_index,
+                                          ir_constant *constant,
+                                          ir_expression *ir2)
+{
+   if (!ir2 || ir1->operation != ir2->operation)
+      return false;
+
+   /* Don't want to even think about matrices. */
+   if (ir1->operands[0]->type->is_matrix() ||
+       ir1->operands[1]->type->is_matrix() ||
+       ir2->operands[0]->type->is_matrix() ||
+       ir2->operands[1]->type->is_matrix())
+      return false;
+
+   ir_constant *ir2_const[2];
+   ir2_const[0] = ir2->operands[0]->constant_expression_value();
+   ir2_const[1] = ir2->operands[1]->constant_expression_value();
+
+   if (ir2_const[0] && ir2_const[1])
+      return false;
+
+   if (ir2_const[0]) {
+      reassociate_operands(ir1, const_index, ir2, 1);
+      return true;
+   } else if (ir2_const[1]) {
+      reassociate_operands(ir1, const_index, ir2, 0);
+      return true;
+   }
+
+   if (reassociate_constant(ir1, const_index, constant,
+                           ir2->operands[0]->as_expression())) {
+      update_type(ir2);
+      return true;
+   }
+
+   if (reassociate_constant(ir1, const_index, constant,
+                           ir2->operands[1]->as_expression())) {
+      update_type(ir2);
+      return true;
+   }
+
+   return false;
+}
+
+/* When eliminating an expression and just returning one of its operands,
+ * we may need to swizzle that operand out to a vector if the expression was
+ * vector type.
+ */
+ir_rvalue *
+ir_algebraic_visitor::swizzle_if_required(ir_expression *expr,
+                                         ir_rvalue *operand)
+{
+   if (expr->type->is_vector() && operand->type->is_scalar()) {
+      return new(mem_ctx) ir_swizzle(operand, 0, 0, 0, 0,
+                                    expr->type->vector_elements);
+   } else
+      return operand;
+}
+
+ir_rvalue *
+ir_algebraic_visitor::handle_expression(ir_expression *ir)
+{
+   ir_constant *op_const[4] = {NULL, NULL, NULL, NULL};
+   ir_expression *op_expr[4] = {NULL, NULL, NULL, NULL};
+   unsigned int i;
+
+   if (ir->operation == ir_binop_mul &&
+       ir->operands[0]->type->is_matrix() &&
+       ir->operands[1]->type->is_vector()) {
+      ir_expression *matrix_mul = ir->operands[0]->as_expression();
+
+      if (matrix_mul && matrix_mul->operation == ir_binop_mul &&
+         matrix_mul->operands[0]->type->is_matrix() &&
+         matrix_mul->operands[1]->type->is_matrix()) {
+
+         return mul(matrix_mul->operands[0],
+                    mul(matrix_mul->operands[1], ir->operands[1]));
+      }
+   }
+
+   assert(ir->get_num_operands() <= 4);
+   for (i = 0; i < ir->get_num_operands(); i++) {
+      if (ir->operands[i]->type->is_matrix())
+        return ir;
+
+      op_const[i] = ir->operands[i]->constant_expression_value();
+      op_expr[i] = ir->operands[i]->as_expression();
+   }
+
+   if (this->mem_ctx == NULL)
+      this->mem_ctx = ralloc_parent(ir);
+
+   switch (ir->operation) {
+   case ir_unop_bit_not:
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_bit_not)
+         return op_expr[0]->operands[0];
+      break;
+
+   case ir_unop_abs:
+      if (op_expr[0] == NULL)
+        break;
+
+      switch (op_expr[0]->operation) {
+      case ir_unop_abs:
+      case ir_unop_neg:
+         return abs(op_expr[0]->operands[0]);
+      default:
+         break;
+      }
+      break;
+
+   case ir_unop_neg:
+      if (op_expr[0] == NULL)
+        break;
+
+      if (op_expr[0]->operation == ir_unop_neg) {
+         return op_expr[0]->operands[0];
+      }
+      break;
+
+   case ir_unop_exp:
+      if (op_expr[0] == NULL)
+        break;
+
+      if (op_expr[0]->operation == ir_unop_log) {
+         return op_expr[0]->operands[0];
+      }
+      break;
+
+   case ir_unop_log:
+      if (op_expr[0] == NULL)
+        break;
+
+      if (op_expr[0]->operation == ir_unop_exp) {
+         return op_expr[0]->operands[0];
+      }
+      break;
+
+   case ir_unop_exp2:
+      if (op_expr[0] == NULL)
+        break;
+
+      if (op_expr[0]->operation == ir_unop_log2) {
+         return op_expr[0]->operands[0];
+      }
+
+      if (!options->EmitNoPow && op_expr[0]->operation == ir_binop_mul) {
+         for (int log2_pos = 0; log2_pos < 2; log2_pos++) {
+            ir_expression *log2_expr =
+               op_expr[0]->operands[log2_pos]->as_expression();
+
+            if (log2_expr && log2_expr->operation == ir_unop_log2) {
+               return new(mem_ctx) ir_expression(ir_binop_pow,
+                                                 ir->type,
+                                                 log2_expr->operands[0],
+                                                 op_expr[0]->operands[1 - log2_pos]);
+            }
+         }
+      }
+      break;
+
+   case ir_unop_log2:
+      if (op_expr[0] == NULL)
+        break;
+
+      if (op_expr[0]->operation == ir_unop_exp2) {
+         return op_expr[0]->operands[0];
+      }
+      break;
+
+   case ir_unop_f2i:
+   case ir_unop_f2u:
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_trunc) {
+         return new(mem_ctx) ir_expression(ir->operation,
+                                           ir->type,
+                                           op_expr[0]->operands[0]);
+      }
+      break;
+
+   case ir_unop_logic_not: {
+      enum ir_expression_operation new_op = ir_unop_logic_not;
+
+      if (op_expr[0] == NULL)
+        break;
+
+      switch (op_expr[0]->operation) {
+      case ir_binop_less:    new_op = ir_binop_gequal;  break;
+      case ir_binop_greater: new_op = ir_binop_lequal;  break;
+      case ir_binop_lequal:  new_op = ir_binop_greater; break;
+      case ir_binop_gequal:  new_op = ir_binop_less;    break;
+      case ir_binop_equal:   new_op = ir_binop_nequal;  break;
+      case ir_binop_nequal:  new_op = ir_binop_equal;   break;
+      case ir_binop_all_equal:   new_op = ir_binop_any_nequal;  break;
+      case ir_binop_any_nequal:  new_op = ir_binop_all_equal;   break;
+
+      default:
+        /* The default case handler is here to silence a warning from GCC.
+         */
+        break;
+      }
+
+      if (new_op != ir_unop_logic_not) {
+        return new(mem_ctx) ir_expression(new_op,
+                                          ir->type,
+                                          op_expr[0]->operands[0],
+                                          op_expr[0]->operands[1]);
+      }
+
+      break;
+   }
+
+   case ir_unop_saturate:
+      if (op_expr[0] && op_expr[0]->operation == ir_binop_add) {
+         ir_expression *b2f_0 = op_expr[0]->operands[0]->as_expression();
+         ir_expression *b2f_1 = op_expr[0]->operands[1]->as_expression();
+
+         if (b2f_0 && b2f_0->operation == ir_unop_b2f &&
+             b2f_1 && b2f_1->operation == ir_unop_b2f) {
+            return b2f(logic_or(b2f_0->operands[0], b2f_1->operands[0]));
+         }
+      }
+      break;
+
+   case ir_binop_add:
+      if (is_vec_zero(op_const[0]))
+        return ir->operands[1];
+      if (is_vec_zero(op_const[1]))
+        return ir->operands[0];
+
+      /* Reassociate addition of constants so that we can do constant
+       * folding.
+       */
+      if (op_const[0] && !op_const[1])
+        reassociate_constant(ir, 0, op_const[0], op_expr[1]);
+      if (op_const[1] && !op_const[0])
+        reassociate_constant(ir, 1, op_const[1], op_expr[0]);
+
+      /* Recognize (v.x + v.y) + (v.z + v.w) as dot(v, 1.0) */
+      if (options->OptimizeForAOS) {
+         ir_expression *expr = try_replace_with_dot(op_expr[0], op_expr[1],
+                                                    mem_ctx);
+         if (expr)
+            return expr;
+      }
+
+      /* Replace (-x + y) * a + x and commutative variations with lrp(x, y, a).
+       *
+       * (-x + y) * a + x
+       * (x * -a) + (y * a) + x
+       * x + (x * -a) + (y * a)
+       * x * (1 - a) + y * a
+       * lrp(x, y, a)
+       */
+      for (int mul_pos = 0; mul_pos < 2; mul_pos++) {
+         ir_expression *mul = op_expr[mul_pos];
+
+         if (!mul || mul->operation != ir_binop_mul)
+            continue;
+
+         /* Multiply found on one of the operands. Now check for an
+          * inner addition operation.
+          */
+         for (int inner_add_pos = 0; inner_add_pos < 2; inner_add_pos++) {
+            ir_expression *inner_add =
+               mul->operands[inner_add_pos]->as_expression();
+
+            if (!inner_add || inner_add->operation != ir_binop_add)
+               continue;
+
+            /* Inner addition found on one of the operands. Now check for
+             * one of the operands of the inner addition to be the negative
+             * of x_operand.
+             */
+            for (int neg_pos = 0; neg_pos < 2; neg_pos++) {
+               ir_expression *neg =
+                  inner_add->operands[neg_pos]->as_expression();
+
+               if (!neg || neg->operation != ir_unop_neg)
+                  continue;
+
+               ir_rvalue *x_operand = ir->operands[1 - mul_pos];
+
+               if (!neg->operands[0]->equals(x_operand))
+                  continue;
+
+               ir_rvalue *y_operand = inner_add->operands[1 - neg_pos];
+               ir_rvalue *a_operand = mul->operands[1 - inner_add_pos];
+
+               if (x_operand->type != y_operand->type ||
+                   x_operand->type != a_operand->type)
+                  continue;
+
+               return lrp(x_operand, y_operand, a_operand);
+            }
+         }
+      }
+
+      break;
+
+   case ir_binop_sub:
+      if (is_vec_zero(op_const[0]))
+        return neg(ir->operands[1]);
+      if (is_vec_zero(op_const[1]))
+        return ir->operands[0];
+      break;
+
+   case ir_binop_mul:
+      if (is_vec_one(op_const[0]))
+        return ir->operands[1];
+      if (is_vec_one(op_const[1]))
+        return ir->operands[0];
+
+      if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1]))
+        return ir_constant::zero(ir, ir->type);
+
+      if (is_vec_negative_one(op_const[0]))
+         return neg(ir->operands[1]);
+      if (is_vec_negative_one(op_const[1]))
+         return neg(ir->operands[0]);
+
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_b2f &&
+          op_expr[1] && op_expr[1]->operation == ir_unop_b2f) {
+         return b2f(logic_and(op_expr[0]->operands[0], op_expr[1]->operands[0]));
+      }
+
+      /* Reassociate multiplication of constants so that we can do
+       * constant folding.
+       */
+      if (op_const[0] && !op_const[1])
+        reassociate_constant(ir, 0, op_const[0], op_expr[1]);
+      if (op_const[1] && !op_const[0])
+        reassociate_constant(ir, 1, op_const[1], op_expr[0]);
+
+      /* Optimizes
+       *
+       *    (mul (floor (add (abs x) 0.5) (sign x)))
+       *
+       * into
+       *
+       *    (trunc (add x (mul (sign x) 0.5)))
+       */
+      for (int i = 0; i < 2; i++) {
+         ir_expression *sign_expr = ir->operands[i]->as_expression();
+         ir_expression *floor_expr = ir->operands[1 - i]->as_expression();
+
+         if (!sign_expr || sign_expr->operation != ir_unop_sign ||
+             !floor_expr || floor_expr->operation != ir_unop_floor)
+            continue;
+
+         ir_expression *add_expr = floor_expr->operands[0]->as_expression();
+         if (!add_expr || add_expr->operation != ir_binop_add)
+            continue;
+
+         for (int j = 0; j < 2; j++) {
+            ir_expression *abs_expr = add_expr->operands[j]->as_expression();
+            if (!abs_expr || abs_expr->operation != ir_unop_abs)
+               continue;
+
+            ir_constant *point_five = add_expr->operands[1 - j]->as_constant();
+            if (!point_five || !point_five->is_value(0.5, 0))
+               continue;
+
+            if (abs_expr->operands[0]->equals(sign_expr->operands[0])) {
+               return trunc(add(abs_expr->operands[0],
+                                mul(sign_expr, point_five)));
+            }
+         }
+      }
+      break;
+
+   case ir_binop_div:
+      if (is_vec_one(op_const[0]) && (
+                ir->type->base_type == GLSL_TYPE_FLOAT ||
+                ir->type->base_type == GLSL_TYPE_DOUBLE)) {
+        return new(mem_ctx) ir_expression(ir_unop_rcp,
+                                          ir->operands[1]->type,
+                                          ir->operands[1],
+                                          NULL);
+      }
+      if (is_vec_one(op_const[1]))
+        return ir->operands[0];
+      break;
+
+   case ir_binop_dot:
+      if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1]))
+        return ir_constant::zero(mem_ctx, ir->type);
+
+      for (int i = 0; i < 2; i++) {
+         if (!op_const[i])
+            continue;
+
+         unsigned components[4] = { 0 }, count = 0;
+
+         for (unsigned c = 0; c < op_const[i]->type->vector_elements; c++) {
+            if (op_const[i]->is_zero())
+               continue;
+
+            components[count] = c;
+            count++;
+         }
+
+         /* No channels had zero values; bail. */
+         if (count >= op_const[i]->type->vector_elements)
+            break;
+
+         ir_expression_operation op = count == 1 ?
+            ir_binop_mul : ir_binop_dot;
+
+         /* Swizzle both operands to remove the channels that were zero. */
+         return new(mem_ctx)
+            ir_expression(op, ir->type,
+                          new(mem_ctx) ir_swizzle(ir->operands[0],
+                                                  components, count),
+                          new(mem_ctx) ir_swizzle(ir->operands[1],
+                                                  components, count));
+      }
+      break;
+
+   case ir_binop_less:
+   case ir_binop_lequal:
+   case ir_binop_greater:
+   case ir_binop_gequal:
+   case ir_binop_equal:
+   case ir_binop_nequal:
+      for (int add_pos = 0; add_pos < 2; add_pos++) {
+         ir_expression *add = op_expr[add_pos];
+
+         if (!add || add->operation != ir_binop_add)
+            continue;
+
+         ir_constant *zero = op_const[1 - add_pos];
+         if (!is_vec_zero(zero))
+            continue;
+
+         /* Depending of the zero position we want to optimize
+          * (0 cmp x+y) into (-x cmp y) or (x+y cmp 0) into (x cmp -y)
+          */
+         if (add_pos == 1) {
+            return new(mem_ctx) ir_expression(ir->operation,
+                                              neg(add->operands[0]),
+                                              add->operands[1]);
+         } else {
+            return new(mem_ctx) ir_expression(ir->operation,
+                                              add->operands[0],
+                                              neg(add->operands[1]));
+         }
+      }
+      break;
+
+   case ir_binop_all_equal:
+   case ir_binop_any_nequal:
+      if (ir->operands[0]->type->is_scalar() &&
+          ir->operands[1]->type->is_scalar())
+         return new(mem_ctx) ir_expression(ir->operation == ir_binop_all_equal
+                                           ? ir_binop_equal : ir_binop_nequal,
+                                           ir->operands[0],
+                                           ir->operands[1]);
+      break;
+
+   case ir_binop_rshift:
+   case ir_binop_lshift:
+      /* 0 >> x == 0 */
+      if (is_vec_zero(op_const[0]))
+         return ir->operands[0];
+      /* x >> 0 == x */
+      if (is_vec_zero(op_const[1]))
+         return ir->operands[0];
+      break;
+
+   case ir_binop_logic_and:
+      if (is_vec_one(op_const[0])) {
+        return ir->operands[1];
+      } else if (is_vec_one(op_const[1])) {
+        return ir->operands[0];
+      } else if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) {
+        return ir_constant::zero(mem_ctx, ir->type);
+      } else if (op_expr[0] && op_expr[0]->operation == ir_unop_logic_not &&
+                 op_expr[1] && op_expr[1]->operation == ir_unop_logic_not) {
+         /* De Morgan's Law:
+          *    (not A) and (not B) === not (A or B)
+          */
+         return logic_not(logic_or(op_expr[0]->operands[0],
+                                   op_expr[1]->operands[0]));
+      } else if (ir->operands[0]->equals(ir->operands[1])) {
+         /* (a && a) == a */
+         return ir->operands[0];
+      }
+      break;
+
+   case ir_binop_logic_xor:
+      if (is_vec_zero(op_const[0])) {
+        return ir->operands[1];
+      } else if (is_vec_zero(op_const[1])) {
+        return ir->operands[0];
+      } else if (is_vec_one(op_const[0])) {
+        return logic_not(ir->operands[1]);
+      } else if (is_vec_one(op_const[1])) {
+        return logic_not(ir->operands[0]);
+      } else if (ir->operands[0]->equals(ir->operands[1])) {
+         /* (a ^^ a) == false */
+        return ir_constant::zero(mem_ctx, ir->type);
+      }
+      break;
+
+   case ir_binop_logic_or:
+      if (is_vec_zero(op_const[0])) {
+        return ir->operands[1];
+      } else if (is_vec_zero(op_const[1])) {
+        return ir->operands[0];
+      } else if (is_vec_one(op_const[0]) || is_vec_one(op_const[1])) {
+        ir_constant_data data;
+
+        for (unsigned i = 0; i < 16; i++)
+           data.b[i] = true;
+
+        return new(mem_ctx) ir_constant(ir->type, &data);
+      } else if (op_expr[0] && op_expr[0]->operation == ir_unop_logic_not &&
+                 op_expr[1] && op_expr[1]->operation == ir_unop_logic_not) {
+         /* De Morgan's Law:
+          *    (not A) or (not B) === not (A and B)
+          */
+         return logic_not(logic_and(op_expr[0]->operands[0],
+                                    op_expr[1]->operands[0]));
+      } else if (ir->operands[0]->equals(ir->operands[1])) {
+         /* (a || a) == a */
+         return ir->operands[0];
+      }
+      break;
+
+   case ir_binop_pow:
+      /* 1^x == 1 */
+      if (is_vec_one(op_const[0]))
+         return op_const[0];
+
+      /* x^1 == x */
+      if (is_vec_one(op_const[1]))
+         return ir->operands[0];
+
+      /* pow(2,x) == exp2(x) */
+      if (is_vec_two(op_const[0]))
+         return expr(ir_unop_exp2, ir->operands[1]);
+
+      if (is_vec_two(op_const[1])) {
+         ir_variable *x = new(ir) ir_variable(ir->operands[1]->type, "x",
+                                              ir_var_temporary);
+         base_ir->insert_before(x);
+         base_ir->insert_before(assign(x, ir->operands[0]));
+         return mul(x, x);
+      }
+
+      if (is_vec_four(op_const[1])) {
+         ir_variable *x = new(ir) ir_variable(ir->operands[1]->type, "x",
+                                              ir_var_temporary);
+         base_ir->insert_before(x);
+         base_ir->insert_before(assign(x, ir->operands[0]));
+
+         ir_variable *squared = new(ir) ir_variable(ir->operands[1]->type,
+                                                    "squared",
+                                                    ir_var_temporary);
+         base_ir->insert_before(squared);
+         base_ir->insert_before(assign(squared, mul(x, x)));
+         return mul(squared, squared);
+      }
+
+      break;
+
+   case ir_binop_min:
+   case ir_binop_max:
+      if (ir->type->base_type != GLSL_TYPE_FLOAT || options->EmitNoSat)
+         break;
+
+      /* Replace min(max) operations and its commutative combinations with
+       * a saturate operation
+       */
+      for (int op = 0; op < 2; op++) {
+         ir_expression *inner_expr = op_expr[op];
+         ir_constant *outer_const = op_const[1 - op];
+         ir_expression_operation op_cond = (ir->operation == ir_binop_max) ?
+            ir_binop_min : ir_binop_max;
+
+         if (!inner_expr || !outer_const || (inner_expr->operation != op_cond))
+            continue;
+
+         /* One of these has to be a constant */
+         if (!inner_expr->operands[0]->as_constant() &&
+             !inner_expr->operands[1]->as_constant())
+            break;
+
+         /* Found a min(max) combination. Now try to see if its operands
+          * meet our conditions that we can do just a single saturate operation
+          */
+         for (int minmax_op = 0; minmax_op < 2; minmax_op++) {
+            ir_rvalue *x = inner_expr->operands[minmax_op];
+            ir_rvalue *y = inner_expr->operands[1 - minmax_op];
+
+            ir_constant *inner_const = y->as_constant();
+            if (!inner_const)
+               continue;
+
+            /* min(max(x, 0.0), 1.0) is sat(x) */
+            if (ir->operation == ir_binop_min &&
+                inner_const->is_zero() &&
+                outer_const->is_one())
+               return saturate(x);
+
+            /* max(min(x, 1.0), 0.0) is sat(x) */
+            if (ir->operation == ir_binop_max &&
+                inner_const->is_one() &&
+                outer_const->is_zero())
+               return saturate(x);
+
+            /* min(max(x, 0.0), b) where b < 1.0 is sat(min(x, b)) */
+            if (ir->operation == ir_binop_min &&
+                inner_const->is_zero() &&
+                is_less_than_one(outer_const))
+               return saturate(expr(ir_binop_min, x, outer_const));
+
+            /* max(min(x, b), 0.0) where b < 1.0 is sat(min(x, b)) */
+            if (ir->operation == ir_binop_max &&
+                is_less_than_one(inner_const) &&
+                outer_const->is_zero())
+               return saturate(expr(ir_binop_min, x, inner_const));
+
+            /* max(min(x, 1.0), b) where b > 0.0 is sat(max(x, b)) */
+            if (ir->operation == ir_binop_max &&
+                inner_const->is_one() &&
+                is_greater_than_zero(outer_const))
+               return saturate(expr(ir_binop_max, x, outer_const));
+
+            /* min(max(x, b), 1.0) where b > 0.0 is sat(max(x, b)) */
+            if (ir->operation == ir_binop_min &&
+                is_greater_than_zero(inner_const) &&
+                outer_const->is_one())
+               return saturate(expr(ir_binop_max, x, inner_const));
+         }
+      }
+
+      break;
+
+   case ir_unop_rcp:
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_rcp)
+        return op_expr[0]->operands[0];
+
+      if (op_expr[0] && (op_expr[0]->operation == ir_unop_exp2 ||
+                         op_expr[0]->operation == ir_unop_exp)) {
+         return new(mem_ctx) ir_expression(op_expr[0]->operation, ir->type,
+                                           neg(op_expr[0]->operands[0]));
+      }
+
+      /* While ir_to_mesa.cpp will lower sqrt(x) to rcp(rsq(x)), it does so at
+       * its IR level, so we can always apply this transformation.
+       */
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_rsq)
+         return sqrt(op_expr[0]->operands[0]);
+
+      /* As far as we know, all backends are OK with rsq. */
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_sqrt) {
+        return rsq(op_expr[0]->operands[0]);
+      }
+
+      break;
+
+   case ir_triop_fma:
+      /* Operands are op0 * op1 + op2. */
+      if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) {
+         return ir->operands[2];
+      } else if (is_vec_zero(op_const[2])) {
+         return mul(ir->operands[0], ir->operands[1]);
+      } else if (is_vec_one(op_const[0])) {
+         return add(ir->operands[1], ir->operands[2]);
+      } else if (is_vec_one(op_const[1])) {
+         return add(ir->operands[0], ir->operands[2]);
+      }
+      break;
+
+   case ir_triop_lrp:
+      /* Operands are (x, y, a). */
+      if (is_vec_zero(op_const[2])) {
+         return ir->operands[0];
+      } else if (is_vec_one(op_const[2])) {
+         return ir->operands[1];
+      } else if (ir->operands[0]->equals(ir->operands[1])) {
+         return ir->operands[0];
+      } else if (is_vec_zero(op_const[0])) {
+         return mul(ir->operands[1], ir->operands[2]);
+      } else if (is_vec_zero(op_const[1])) {
+         unsigned op2_components = ir->operands[2]->type->vector_elements;
+         ir_constant *one;
+
+         switch (ir->type->base_type) {
+         case GLSL_TYPE_FLOAT:
+            one = new(mem_ctx) ir_constant(1.0f, op2_components);
+            break;
+         case GLSL_TYPE_DOUBLE:
+            one = new(mem_ctx) ir_constant(1.0, op2_components);
+            break;
+         default:
+            one = NULL;
+            unreachable("unexpected type");
+         }
+
+         return mul(ir->operands[0], add(one, neg(ir->operands[2])));
+      }
+      break;
+
+   case ir_triop_csel:
+      if (is_vec_one(op_const[0]))
+        return ir->operands[1];
+      if (is_vec_zero(op_const[0]))
+        return ir->operands[2];
+      break;
+
+   default:
+      break;
+   }
+
+   return ir;
+}
+
+void
+ir_algebraic_visitor::handle_rvalue(ir_rvalue **rvalue)
+{
+   if (!*rvalue)
+      return;
+
+   ir_expression *expr = (*rvalue)->as_expression();
+   if (!expr || expr->operation == ir_quadop_vector)
+      return;
+
+   ir_rvalue *new_rvalue = handle_expression(expr);
+   if (new_rvalue == *rvalue)
+      return;
+
+   /* If the expr used to be some vec OP scalar returning a vector, and the
+    * optimization gave us back a scalar, we still need to turn it into a
+    * vector.
+    */
+   *rvalue = swizzle_if_required(expr, new_rvalue);
+
+   this->progress = true;
+}
+
+bool
+do_algebraic(exec_list *instructions, bool native_integers,
+             const struct gl_shader_compiler_options *options)
+{
+   ir_algebraic_visitor v(native_integers, options);
+
+   visit_list_elements(&v, instructions);
+
+   return v.progress;
+}