With the more advanced dead code elimination pass already being run,
eliminate_dead_code was making no difference in instruction count, and had
an undesirable O(n^2) runtime. So remove it and rename
eliminate_dead_code_advanced to eliminate_dead_code.
---
src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 50 +++-------------------------
1 file changed, 5 insertions(+), 45 deletions(-)
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 6eb6c8a..b0e0782 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -460,8 +460,7 @@ public:
int get_last_temp_write(int index);
void copy_propagate(void);
- void eliminate_dead_code(void);
- int eliminate_dead_code_advanced(void);
+ int eliminate_dead_code(void);
void merge_registers(void);
void renumber_registers(void);
@@ -3663,7 +3662,8 @@ glsl_to_tgsi_visitor::copy_propagate(void)
}
/*
- * Tracks available PROGRAM_TEMPORARY registers for dead code elimination.
+ * On a basic block basis, tracks available PROGRAM_TEMPORARY registers for
dead
+ * code elimination.
*
* The glsl_to_tgsi_visitor lazily produces code assuming that this pass
* will occur. As an example, a TXP production after copy propagation but
@@ -3676,48 +3676,9 @@ glsl_to_tgsi_visitor::copy_propagate(void)
* and after this pass:
*
* 0: TXP TEMP[2], INPUT[4].xyyw, texture[0], 2D;
- *
- * FIXME: assumes that all functions are inlined (no support for BGNSUB/ENDSUB)
- * FIXME: doesn't eliminate all dead code inside of loops; it steps around them
- */
-void
-glsl_to_tgsi_visitor::eliminate_dead_code(void)
-{
- int i;
-
- for (i=0; i < this->next_temp; i++) {
- int last_read = get_last_temp_read(i);
- int j = 0;
-
- foreach_list_safe(node, &this->instructions) {
- glsl_to_tgsi_instruction *inst = (glsl_to_tgsi_instruction *) node;
-
- if (inst->dst.file == PROGRAM_TEMPORARY && inst->dst.index == i &&
- j > last_read)
- {
- inst->remove();
- delete inst;
- }
-
- j++;
- }
- }
-}
-
-/*
- * On a basic block basis, tracks available PROGRAM_TEMPORARY registers for
dead
- * code elimination. This is less primitive than eliminate_dead_code(), as it
- * is per-channel and can detect consecutive writes without a read between them
- * as dead code. However, there is some dead code that can be eliminated by
- * eliminate_dead_code() but not this function - for example, this function
- * cannot eliminate an instruction writing to a register that is never read and
- * is the only instruction writing to that register.
- *
- * The glsl_to_tgsi_visitor lazily produces code assuming that this pass
- * will occur.
*/
int
-glsl_to_tgsi_visitor::eliminate_dead_code_advanced(void)
+glsl_to_tgsi_visitor::eliminate_dead_code(void)
{
glsl_to_tgsi_instruction **writes = rzalloc_array(mem_ctx,
glsl_to_tgsi_instruction
*,
@@ -5245,9 +5206,8 @@ get_mesa_program(struct gl_context *ctx,
/* Perform optimizations on the instructions in the glsl_to_tgsi_visitor. */
v->simplify_cmp();
v->copy_propagate();
- while (v->eliminate_dead_code_advanced());
+ while (v->eliminate_dead_code());
- v->eliminate_dead_code();
v->merge_registers();
v->renumber_registers();
--
1.7.9.5
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