glsl: Combine many instruction lowering passes into one.

This should save on the overhead of tree-walking and provide a
convenient place to add more instruction lowering in the future.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>

11 files changed, 281 insertions, 383 deletions

diff --git a/src/glsl/Makefile b/src/glsl/Makefile
index ea4d6be5a4..f5aadc347b 100644
--- a/src/glsl/Makefile
+++ b/src/glsl/Makefile
@@ -52,14 +52,11 @@ CXX_SOURCES = \
 	loop_analysis.cpp \
 	loop_controls.cpp \
 	loop_unroll.cpp \
-	lower_div_to_mul_rcp.cpp \
-	lower_explog_to_explog2.cpp \
 	lower_if_to_cond_assign.cpp \
+	lower_instructions.cpp \
 	lower_jumps.cpp \
 	lower_mat_op_to_vec.cpp \
-	lower_mod_to_fract.cpp \
 	lower_noise.cpp \
-	lower_sub_to_add_neg.cpp \
 	lower_texture_projection.cpp \
 	lower_variable_index_to_cond_assign.cpp \
 	lower_vec_index_to_cond_assign.cpp \
diff --git a/src/glsl/SConscript b/src/glsl/SConscript
index 4cb2d8bcb3..f708635e53 100644
--- a/src/glsl/SConscript
+++ b/src/glsl/SConscript
@@ -49,14 +49,11 @@ sources = [
     'loop_analysis.cpp',
     'loop_controls.cpp',
     'loop_unroll.cpp',
-    'lower_div_to_mul_rcp.cpp',
-    'lower_explog_to_explog2.cpp',
     'lower_if_to_cond_assign.cpp',
+    'lower_instructions.cpp',
     'lower_jumps.cpp',
     'lower_mat_op_to_vec.cpp',
-    'lower_mod_to_fract.cpp',
     'lower_noise.cpp',
-    'lower_sub_to_add_neg.cpp',
     'lower_variable_index_to_cond_assign.cpp',
     'lower_vec_index_to_cond_assign.cpp',
     'lower_vec_index_to_swizzle.cpp',
diff --git a/src/glsl/glsl_parser_extras.cpp b/src/glsl/glsl_parser_extras.cpp
index b2c378dd85..302cfbc566 100644
--- a/src/glsl/glsl_parser_extras.cpp
+++ b/src/glsl/glsl_parser_extras.cpp
@@ -708,7 +708,7 @@ do_common_optimization(exec_list *ir, bool linked, unsigned max_unroll_iteration
 {
    GLboolean progress = GL_FALSE;
 
-   progress = do_sub_to_add_neg(ir) || progress;
+   progress = lower_instructions(ir, SUB_TO_ADD_NEG) || progress;
 
    if (linked) {
       progress = do_function_inlining(ir) || progress;
diff --git a/src/glsl/ir_optimization.h b/src/glsl/ir_optimization.h
index 1f8da16bcb..fa497a4555 100644
--- a/src/glsl/ir_optimization.h
+++ b/src/glsl/ir_optimization.h
@@ -28,6 +28,13 @@
  * Prototypes for optimization passes to be called by the compiler and drivers.
  */
 
+/* Operations for lower_instructions() */
+#define SUB_TO_ADD_NEG 0x01
+#define DIV_TO_MUL_RCP 0x02
+#define EXP_TO_EXP2    0x04
+#define LOG_TO_LOG2    0x08
+#define MOD_TO_FRACT   0x10
+
 bool do_common_optimization(exec_list *ir, bool linked, unsigned max_unroll_iterations);
 
 bool do_algebraic(exec_list *instructions);
@@ -40,8 +47,6 @@ bool do_dead_code(exec_list *instructions);
 bool do_dead_code_local(exec_list *instructions);
 bool do_dead_code_unlinked(exec_list *instructions);
 bool do_dead_functions(exec_list *instructions);
-bool do_div_to_mul_rcp(exec_list *instructions);
-bool do_explog_to_explog2(exec_list *instructions);
 bool do_function_inlining(exec_list *instructions);
 bool do_lower_jumps(exec_list *instructions, bool pull_out_jumps = true, bool lower_sub_return = true, bool lower_main_return = false, bool lower_continue = false, bool lower_break = false);
 bool do_lower_texture_projection(exec_list *instructions);
@@ -56,6 +61,7 @@ bool do_swizzle_swizzle(exec_list *instructions);
 bool do_tree_grafting(exec_list *instructions);
 bool do_vec_index_to_cond_assign(exec_list *instructions);
 bool do_vec_index_to_swizzle(exec_list *instructions);
+bool lower_instructions(exec_list *instructions, unsigned what_to_lower);
 bool lower_noise(exec_list *instructions);
 bool lower_variable_index_to_cond_assign(exec_list *instructions,
     bool lower_input, bool lower_output, bool lower_temp, bool lower_uniform);
diff --git a/src/glsl/lower_div_to_mul_rcp.cpp b/src/glsl/lower_div_to_mul_rcp.cpp
deleted file mode 100644
index db9d6854cd..0000000000
--- a/src/glsl/lower_div_to_mul_rcp.cpp
+++ /dev/null
@@ -1,114 +0,0 @@
-/*
- * 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_div_to_mul_rcp.cpp
- *
- * Breaks an ir_unop_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.
- */
-
-#include "ir.h"
-#include "glsl_types.h"
-
-class ir_div_to_mul_rcp_visitor : public ir_hierarchical_visitor {
-public:
-   ir_div_to_mul_rcp_visitor()
-   {
-      this->made_progress = false;
-   }
-
-   ir_visitor_status visit_leave(ir_expression *);
-
-   bool made_progress;
-};
-
-bool
-do_div_to_mul_rcp(exec_list *instructions)
-{
-   ir_div_to_mul_rcp_visitor v;
-
-   visit_list_elements(&v, instructions);
-   return v.made_progress;
-}
-
-ir_visitor_status
-ir_div_to_mul_rcp_visitor::visit_leave(ir_expression *ir)
-{
-   if (ir->operation != ir_binop_div)
-      return visit_continue;
-
-   if (!ir->operands[1]->type->is_integer()) {
-      /* 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],
-				   NULL);
-
-      /* op0 / op1 -> op0 * (1.0 / op1) */
-      ir->operation = ir_binop_mul;
-      ir->operands[1] = expr;
-   } else {
-      /* 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);
-
-      op0 = new(ir) ir_expression(ir_binop_mul, vec_type, op0, op1);
-
-      ir->operation = ir_unop_f2i;
-      ir->operands[0] = op0;
-      ir->operands[1] = NULL;
-   }
-
-   this->made_progress = true;
-
-   return visit_continue;
-}
diff --git a/src/glsl/lower_explog_to_explog2.cpp b/src/glsl/lower_explog_to_explog2.cpp
deleted file mode 100644
index 8ad0262544..0000000000
--- a/src/glsl/lower_explog_to_explog2.cpp
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * 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_explog_to_explog2.cpp
- *
- * 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.
- */
-
-#include "main/core.h" /* for log2f on MSVC */
-#include "ir.h"
-#include "glsl_types.h"
-
-class ir_explog_to_explog2_visitor : public ir_hierarchical_visitor {
-public:
-   ir_explog_to_explog2_visitor()
-   {
-      this->progress = false;
-   }
-
-   ir_visitor_status visit_leave(ir_expression *);
-
-   bool progress;
-};
-
-bool
-do_explog_to_explog2(exec_list *instructions)
-{
-   ir_explog_to_explog2_visitor v;
-
-   visit_list_elements(&v, instructions);
-   return v.progress;
-}
-
-ir_visitor_status
-ir_explog_to_explog2_visitor::visit_leave(ir_expression *ir)
-{
-   if (ir->operation == ir_unop_exp) {
-      void *mem_ctx = talloc_parent(ir);
-      ir_constant *log2_e = new(mem_ctx) ir_constant(log2f(M_E));
-
-      ir->operation = ir_unop_exp2;
-      ir->operands[0] = new(mem_ctx) ir_expression(ir_binop_mul,
-						   ir->operands[0]->type,
-						   ir->operands[0],
-						   log2_e);
-      this->progress = true;
-   }
-
-   if (ir->operation == ir_unop_log) {
-      void *mem_ctx = talloc_parent(ir);
-
-      ir->operation = ir_binop_mul;
-      ir->operands[0] = new(mem_ctx) ir_expression(ir_unop_log2,
-						   ir->operands[0]->type,
-						   ir->operands[0],
-						   NULL);
-      ir->operands[1] = new(mem_ctx) ir_constant(1.0f / log2f(M_E));
-      this->progress = true;
-   }
-
-   return visit_continue;
-}
diff --git a/src/glsl/lower_instructions.cpp b/src/glsl/lower_instructions.cpp
new file mode 100644
index 0000000000..d460ba1a97
--- /dev/null
+++ b/src/glsl/lower_instructions.cpp
@@ -0,0 +1,262 @@
+/*
+ * 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
+ * - EXP_TO_EXP2
+ * - LOG_TO_LOG2
+ * - MOD_TO_FRACT
+ *
+ * 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:
+ * ---------------
+ * Breaks an ir_unop_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.
+ *
+ * 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.
+ *
+ * MOD_TO_FRACT:
+ * -------------
+ * Breaks an ir_unop_mod expression down to (op1 * fract(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.
+ */
+
+#include "main/core.h" /* for M_E */
+#include "glsl_types.h"
+#include "ir.h"
+#include "ir_optimization.h"
+
+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 mod_to_fract(ir_expression *);
+   void exp_to_exp2(ir_expression *);
+   void log_to_log2(ir_expression *);
+};
+
+/**
+ * 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)
+{
+   if (!ir->operands[1]->type->is_integer()) {
+      /* 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],
+				   NULL);
+
+      /* op0 / op1 -> op0 * (1.0 / op1) */
+      ir->operation = ir_binop_mul;
+      ir->operands[1] = expr;
+   } else {
+      /* 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);
+
+      op0 = new(ir) ir_expression(ir_binop_mul, vec_type, op0, op1);
+
+      ir->operation = ir_unop_f2i;
+      ir->operands[0] = 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(log2f(M_E));
+
+   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::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(1.0f / log2f(M_E));
+   this->progress = true;
+}
+
+void
+lower_instructions_visitor::mod_to_fract(ir_expression *ir)
+{
+   ir_variable *temp = new(ir) ir_variable(ir->operands[1]->type, "mod_b",
+					   ir_var_temporary);
+   this->base_ir->insert_before(temp);
+
+   ir_assignment *const assign =
+      new(ir) ir_assignment(new(ir) ir_dereference_variable(temp),
+			    ir->operands[1], NULL);
+
+   this->base_ir->insert_before(assign);
+
+   ir_expression *const div_expr =
+      new(ir) ir_expression(ir_binop_div, ir->operands[0]->type,
+			    ir->operands[0],
+			    new(ir) ir_dereference_variable(temp));
+
+   /* Don't generate new IR that would need to be lowered in an additional
+    * pass.
+    */
+   if (lowering(DIV_TO_MUL_RCP))
+      div_to_mul_rcp(div_expr);
+
+   ir_rvalue *expr = new(ir) ir_expression(ir_unop_fract,
+					   ir->operands[0]->type,
+					   div_expr,
+					   NULL);
+
+   ir->operation = ir_binop_mul;
+   ir->operands[0] = new(ir) ir_dereference_variable(temp);
+   ir->operands[1] = expr;
+   this->progress = true;
+}
+
+ir_visitor_status
+lower_instructions_visitor::visit_leave(ir_expression *ir)
+{
+   switch (ir->operation) {
+   case ir_binop_sub:
+      if (lowering(SUB_TO_ADD_NEG))
+	 sub_to_add_neg(ir);
+      break;
+
+   case ir_binop_div:
+      if (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_FRACT))
+	 mod_to_fract(ir);
+      break;
+
+   default:
+      return visit_continue;
+   }
+
+   return visit_continue;
+}
diff --git a/src/glsl/lower_mod_to_fract.cpp b/src/glsl/lower_mod_to_fract.cpp
deleted file mode 100644
index ff907ae97c..0000000000
--- a/src/glsl/lower_mod_to_fract.cpp
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * 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_mod_to_fract.cpp
- *
- * Breaks an ir_unop_mod expression down to (op1 * fract(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.
- */
-
-#include "ir.h"
-
-class ir_mod_to_fract_visitor : public ir_hierarchical_visitor {
-public:
-   ir_mod_to_fract_visitor()
-   {
-      this->made_progress = false;
-   }
-
-   ir_visitor_status visit_leave(ir_expression *);
-
-   bool made_progress;
-};
-
-bool
-do_mod_to_fract(exec_list *instructions)
-{
-   ir_mod_to_fract_visitor v;
-
-   visit_list_elements(&v, instructions);
-   return v.made_progress;
-}
-
-ir_visitor_status
-ir_mod_to_fract_visitor::visit_leave(ir_expression *ir)
-{
-   if (ir->operation != ir_binop_mod)
-      return visit_continue;
-
-   ir_variable *temp = new(ir) ir_variable(ir->operands[1]->type, "mod_b",
-					   ir_var_temporary);
-   this->base_ir->insert_before(temp);
-
-   ir_assignment *assign;
-   ir_rvalue *expr;
-
-   assign = new(ir) ir_assignment(new(ir) ir_dereference_variable(temp),
-				  ir->operands[1], NULL);
-   this->base_ir->insert_before(assign);
-
-   expr = new(ir) ir_expression(ir_binop_div,
-				ir->operands[0]->type,
-				ir->operands[0],
-				new(ir) ir_dereference_variable(temp));
-
-   expr = new(ir) ir_expression(ir_unop_fract,
-				ir->operands[0]->type,
-				expr,
-				NULL);
-
-   ir->operation = ir_binop_mul;
-   ir->operands[0] = new(ir) ir_dereference_variable(temp);
-   ir->operands[1] = expr;
-   this->made_progress = true;
-
-   return visit_continue;
-}
diff --git a/src/glsl/lower_sub_to_add_neg.cpp b/src/glsl/lower_sub_to_add_neg.cpp
deleted file mode 100644
index 9e4019709b..0000000000
--- a/src/glsl/lower_sub_to_add_neg.cpp
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- * 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_sub_to_add_neg.cpp
- *
- * 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.
- */
-
-#include "ir.h"
-
-class ir_sub_to_add_neg_visitor : public ir_hierarchical_visitor {
-public:
-   ir_sub_to_add_neg_visitor()
-   {
-      this->progress = false;
-   }
-
-   ir_visitor_status visit_leave(ir_expression *);
-
-   bool progress;
-};
-
-bool
-do_sub_to_add_neg(exec_list *instructions)
-{
-   ir_sub_to_add_neg_visitor v;
-
-   visit_list_elements(&v, instructions);
-   return v.progress;
-}
-
-ir_visitor_status
-ir_sub_to_add_neg_visitor::visit_leave(ir_expression *ir)
-{
-   if (ir->operation != ir_binop_sub)
-      return visit_continue;
-
-   void *mem_ctx = talloc_parent(ir);
-
-   ir->operation = ir_binop_add;
-   ir->operands[1] = new(mem_ctx) ir_expression(ir_unop_neg,
-						ir->operands[1]->type,
-						ir->operands[1],
-						NULL);
-
-   this->progress = true;
-
-   return visit_continue;
-}
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index e1cb94452d..610b7e3c3e 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -101,10 +101,12 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
       clone_ir_list(mem_ctx, shader->ir, shader->base.ir);
 
       do_mat_op_to_vec(shader->ir);
-      do_mod_to_fract(shader->ir);
-      do_div_to_mul_rcp(shader->ir);
-      do_sub_to_add_neg(shader->ir);
-      do_explog_to_explog2(shader->ir);
+      lower_instructions(shader->ir,
+			 MOD_TO_FRACT |
+			 DIV_TO_MUL_RCP |
+			 SUB_TO_ADD_NEG |
+			 EXP_TO_EXP2 |
+			 LOG_TO_LOG2);
       do_lower_texture_projection(shader->ir);
       brw_do_cubemap_normalize(shader->ir);
 
diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index 1cb8183042..c7a8594f72 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -2798,9 +2798,8 @@ _mesa_ir_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
 
 	 /* Lowering */
 	 do_mat_op_to_vec(ir);
-	 do_mod_to_fract(ir);
-	 do_div_to_mul_rcp(ir);
-	 do_explog_to_explog2(ir);
+	 lower_instructions(ir, MOD_TO_FRACT | DIV_TO_MUL_RCP | EXP_TO_EXP2
+			      | LOG_TO_LOG2);
 
 	 progress = do_lower_jumps(ir, true, true, options->EmitNoMainReturn, options->EmitNoCont, options->EmitNoLoops) || progress;