xserver mesa git update 15 May 2012

7 files changed, 157 insertions, 209 deletions

diff --git a/mesalib/src/glsl/Makefile.sources b/mesalib/src/glsl/Makefile.sources
index 5621e42b2..fba03604c 100644
--- a/mesalib/src/glsl/Makefile.sources
+++ b/mesalib/src/glsl/Makefile.sources
@@ -51,6 +51,7 @@ LIBGLSL_CXX_FILES := \
 	loop_unroll.cpp \
 	lower_clip_distance.cpp \
 	lower_discard.cpp \
+	lower_discard_flow.cpp \
 	lower_if_to_cond_assign.cpp \
 	lower_instructions.cpp \
 	lower_jumps.cpp \
@@ -72,7 +73,6 @@ LIBGLSL_CXX_FILES := \
 	opt_dead_code.cpp \
 	opt_dead_code_local.cpp \
 	opt_dead_functions.cpp \
-	opt_discard_simplification.cpp \
 	opt_function_inlining.cpp \
 	opt_if_simplification.cpp \
 	opt_noop_swizzle.cpp \
diff --git a/mesalib/src/glsl/glsl_parser_extras.cpp b/mesalib/src/glsl/glsl_parser_extras.cpp
index 6f1c86b43..46f21dd07 100644
--- a/mesalib/src/glsl/glsl_parser_extras.cpp
+++ b/mesalib/src/glsl/glsl_parser_extras.cpp
@@ -1044,7 +1044,6 @@ do_common_optimization(exec_list *ir, bool linked,
       progress = do_structure_splitting(ir) || progress;
    }
    progress = do_if_simplification(ir) || progress;
-   progress = do_discard_simplification(ir) || progress;
    progress = do_copy_propagation(ir) || progress;
    progress = do_copy_propagation_elements(ir) || progress;
    if (linked)
diff --git a/mesalib/src/glsl/ir_optimization.h b/mesalib/src/glsl/ir_optimization.h
index 356783583..c435d7717 100644
--- a/mesalib/src/glsl/ir_optimization.h
+++ b/mesalib/src/glsl/ir_optimization.h
@@ -66,6 +66,7 @@ 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_discard(exec_list *instructions);
+void lower_discard_flow(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,
diff --git a/mesalib/src/glsl/linker.cpp b/mesalib/src/glsl/linker.cpp
index 6ba297237..bdab499f0 100644
--- a/mesalib/src/glsl/linker.cpp
+++ b/mesalib/src/glsl/linker.cpp
@@ -2296,6 +2296,17 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
       prog->LinkStatus = true;
    }
 
+   /* Implement the GLSL 1.30+ rule for discard vs infinite loops Do
+    * it before optimization because we want most of the checks to get
+    * dropped thanks to constant propagation.
+    */
+   if (max_version >= 130) {
+      struct gl_shader *sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
+      if (sh) {
+	 lower_discard_flow(sh->ir);
+      }
+   }
+
    /* Do common optimization before assigning storage for attributes,
     * uniforms, and varyings.  Later optimization could possibly make
     * some of that unused.
diff --git a/mesalib/src/glsl/lower_discard_flow.cpp b/mesalib/src/glsl/lower_discard_flow.cpp
new file mode 100644
index 000000000..d385c1435
--- /dev/null
+++ b/mesalib/src/glsl/lower_discard_flow.cpp
@@ -0,0 +1,144 @@
+/*
+ * 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_discard_flow.cpp
+ *
+ * Implements the GLSL 1.30 revision 9 rule for fragment shader
+ * discard handling:
+ *
+ *     "Control flow exits the shader, and subsequent implicit or
+ *      explicit derivatives are undefined when this control flow is
+ *      non-uniform (meaning different fragments within the primitive
+ *      take different control paths)."
+ *
+ * There seem to be two conflicting things here.  "Control flow exits
+ * the shader" sounds like the discarded fragments should effectively
+ * jump to the end of the shader, but that breaks derivatives in the
+ * case of uniform control flow and causes rendering failure in the
+ * bushes in Unigine Tropics.
+ *
+ * The question, then, is whether the intent was "loops stop at the
+ * point that the only active channels left are discarded pixels" or
+ * "discarded pixels become inactive at the point that control flow
+ * returns to the top of a loop".  This implements the second
+ * interpretation.
+ */
+
+#include "glsl_types.h"
+#include "ir.h"
+#include "program/hash_table.h"
+
+class lower_discard_flow_visitor : public ir_hierarchical_visitor {
+public:
+   lower_discard_flow_visitor(ir_variable *discarded)
+   : discarded(discarded)
+   {
+      mem_ctx = ralloc_parent(discarded);
+   }
+
+   ~lower_discard_flow_visitor()
+   {
+   }
+
+   ir_visitor_status visit_enter(ir_discard *ir);
+   ir_visitor_status visit_enter(ir_loop_jump *ir);
+   ir_visitor_status visit_enter(ir_loop *ir);
+   ir_visitor_status visit_enter(ir_function_signature *ir);
+
+   ir_if *generate_discard_break();
+
+   ir_variable *discarded;
+   void *mem_ctx;
+};
+
+ir_visitor_status
+lower_discard_flow_visitor::visit_enter(ir_loop_jump *ir)
+{
+   if (ir->mode != ir_loop_jump::jump_continue)
+      return visit_continue;
+
+   ir->insert_before(generate_discard_break());
+
+   return visit_continue;
+}
+
+ir_visitor_status
+lower_discard_flow_visitor::visit_enter(ir_discard *ir)
+{
+   ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(discarded);
+   ir_rvalue *rhs = new(mem_ctx) ir_constant(true);
+   ir_assignment *assign = new(mem_ctx) ir_assignment(lhs, rhs);
+   ir->insert_before(assign);
+
+   return visit_continue;
+}
+
+ir_visitor_status
+lower_discard_flow_visitor::visit_enter(ir_loop *ir)
+{
+   ir->body_instructions.push_tail(generate_discard_break());
+
+   return visit_continue;
+}
+
+ir_visitor_status
+lower_discard_flow_visitor::visit_enter(ir_function_signature *ir)
+{
+   if (strcmp(ir->function_name(), "main") != 0)
+      return visit_continue;
+
+   ir_dereference *lhs = new(mem_ctx) ir_dereference_variable(discarded);
+   ir_rvalue *rhs = new(mem_ctx) ir_constant(false);
+   ir_assignment *assign = new(mem_ctx) ir_assignment(lhs, rhs);
+   ir->body.push_head(assign);
+
+   return visit_continue;
+}
+
+ir_if *
+lower_discard_flow_visitor::generate_discard_break()
+{
+   ir_rvalue *if_condition = new(mem_ctx) ir_dereference_variable(discarded);
+   ir_if *if_inst = new(mem_ctx) ir_if(if_condition);
+
+   ir_instruction *br = new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_break);
+   if_inst->then_instructions.push_tail(br);
+
+   return if_inst;
+}
+
+void
+lower_discard_flow(exec_list *ir)
+{
+   void *mem_ctx = ir;
+
+   ir_variable *var = new(mem_ctx) ir_variable(glsl_type::bool_type,
+					       "discarded",
+					       ir_var_temporary);
+
+   ir->push_head(var);
+
+   lower_discard_flow_visitor v(var);
+
+   visit_list_elements(&v, ir);
+}
diff --git a/mesalib/src/glsl/opt_discard_simplification.cpp b/mesalib/src/glsl/opt_discard_simplification.cpp
deleted file mode 100644
index ba4981bae..000000000
--- a/mesalib/src/glsl/opt_discard_simplification.cpp
+++ /dev/null
@@ -1,205 +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 opt_discard_simplification.cpp
- *
- * This pass simplifies if-statements and loops containing unconditional
- * discards.
- *
- * Case 1: Both branches contain unconditional discards:
- * -----------------------------------------------------
- *
- *    if (cond) {
- *	 s1;
- *	 discard;
- *	 s2;
- *    } else {
- *	 s3;
- *	 discard;
- *	 s4;
- *    }
- *
- * becomes:
- *
- *    discard
- *
- * Case 2: The "then" clause contains an unconditional discard:
- * ------------------------------------------------------------
- *
- *    if (cond) {
- *       s1;
- *       discard;
- *       s2;
- *    } else {
- *	 s3;
- *    }
- *
- * becomes:
- *
- *    if (cond) {
- *	 discard;
- *    } else {
- *	 s3;
- *    }
- *
- * Case 3: The "else" clause contains an unconditional discard:
- * ------------------------------------------------------------
- *
- *    if (cond) {
- *       s1;
- *    } else {
- *       s2;
- *       discard;
- *	 s3;
- *    }
- *
- * becomes:
- *
- *    if (cond) {
- *	 s1;
- *    } else {
- *	 discard;
- *    }
- */
-
-#include "glsl_types.h"
-#include "ir.h"
-
-class discard_simplifier : public ir_hierarchical_visitor {
-public:
-   discard_simplifier()
-   {
-      this->progress = false;
-   }
-
-   ir_visitor_status visit_enter(ir_if *);
-   ir_visitor_status visit_enter(ir_loop *);
-   ir_visitor_status visit_enter(ir_assignment *);
-
-   bool progress;
-};
-
-static ir_discard *
-find_unconditional_discard(exec_list &instructions)
-{
-   foreach_list(n, &instructions) {
-      ir_instruction *ir = (ir_instruction *)n;
-
-      if (ir->ir_type == ir_type_return ||
-	  ir->ir_type == ir_type_loop_jump)
-	 return NULL;
-
-      /* So far, this code doesn't know how to look inside of flow
-       * control to see if a discard later on at this level is
-       * unconditional.
-       */
-      if (ir->ir_type == ir_type_if ||
-	  ir->ir_type == ir_type_loop)
-	 return NULL;
-
-      ir_discard *discard = ir->as_discard();
-      if (discard != NULL && discard->condition == NULL)
-	 return discard;
-   }
-   return NULL;
-}
-
-static bool
-is_only_instruction(ir_discard *discard)
-{
-   return (discard->prev->is_head_sentinel() &&
-	   discard->next->is_tail_sentinel());
-}
-
-/* We only care about the top level instructions, so don't descend
- * into expressions.
- */
-ir_visitor_status
-discard_simplifier::visit_enter(ir_assignment *ir)
-{
-   (void) ir;
-   return visit_continue_with_parent;
-}
-
-ir_visitor_status
-discard_simplifier::visit_enter(ir_if *ir)
-{
-   ir_discard *then_discard = find_unconditional_discard(ir->then_instructions);
-   ir_discard *else_discard = find_unconditional_discard(ir->else_instructions);
-
-   if (then_discard == NULL && else_discard == NULL)
-      return visit_continue;
-
-   /* If both branches result in discard, replace whole if with discard. */
-   if (then_discard != NULL && else_discard != NULL) {
-      this->progress = true;
-      ir->replace_with(then_discard);
-      return visit_continue_with_parent;
-   }
-
-   /* Otherwise, one branch has a discard. */
-   if (then_discard != NULL && !is_only_instruction(then_discard)) {
-      this->progress = true;
-      ir->then_instructions.make_empty();
-      ir->then_instructions.push_tail(then_discard);
-   } else if (else_discard != NULL && !is_only_instruction(else_discard)) {
-      this->progress = true;
-      ir->else_instructions.make_empty();
-      ir->else_instructions.push_tail(else_discard);
-   }
-
-   visit_list_elements(this, &ir->then_instructions);
-   return visit_continue_with_parent;
-}
-
-ir_visitor_status
-discard_simplifier::visit_enter(ir_loop *ir)
-{
-   ir_discard *discard = find_unconditional_discard(ir->body_instructions);
-
-   if (discard) {
-      ir->replace_with(discard);
-      return visit_continue_with_parent;
-   }
-
-   return visit_continue;
-}
-
-bool
-do_discard_simplification(exec_list *instructions)
-{
-   /* Look for a top-level unconditional discard */
-   ir_discard *discard = find_unconditional_discard(*instructions);
-   if (discard != NULL) {
-      instructions->make_empty();
-      instructions->push_tail(discard);
-      return true;
-   }
-
-   discard_simplifier v;
-
-   visit_list_elements(&v, instructions);
-
-   return v.progress;
-}
diff --git a/mesalib/src/glsl/test_optpass.cpp b/mesalib/src/glsl/test_optpass.cpp
index 6abafb5d3..31f65c3d2 100644
--- a/mesalib/src/glsl/test_optpass.cpp
+++ b/mesalib/src/glsl/test_optpass.cpp
@@ -98,8 +98,6 @@ do_optimization(struct exec_list *ir, const char *optimization)
       return do_lower_texture_projection(ir);
    } else if (strcmp(optimization, "do_if_simplification") == 0) {
       return do_if_simplification(ir);
-   } else if (strcmp(optimization, "do_discard_simplification") == 0) {
-      return do_discard_simplification(ir);
    } else if (sscanf(optimization, "lower_if_to_cond_assign ( %d ) ",
                      &int_0) == 1) {
       return lower_if_to_cond_assign(ir, int_0);