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authorTom Stellard <tstellar@gmail.com>2010-06-05 12:59:02 -0700
committerMarek Olšák <maraeo@gmail.com>2010-06-11 22:06:58 +0200
commit6f1b6814bcaeb375a15277547376b0f909a52123 (patch)
treed94854bd2ebcc92aa5bf806478d28a487de2902f /src/mesa
parent0f1109ce3613b61bf3c502beb422af8d43ff7b9b (diff)
r300/compiler: Unroll loops that decrement the counter.
e.g. for(i=10; i>0; i--)
Diffstat (limited to 'src/mesa')
-rw-r--r--src/mesa/drivers/dri/r300/compiler/radeon_emulate_loops.c132
1 files changed, 83 insertions, 49 deletions
diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_emulate_loops.c b/src/mesa/drivers/dri/r300/compiler/radeon_emulate_loops.c
index 21a9f31a66..859023a4d8 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_emulate_loops.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_emulate_loops.c
@@ -34,6 +34,10 @@
#include "radeon_compiler.h"
#include "radeon_dataflow.h"
+#define VERBOSE 0
+
+#define DBG(...) do { if (VERBOSE) fprintf(stderr, __VA_ARGS__); } while(0)
+
struct emulate_loop_state {
struct radeon_compiler * C;
struct loop_info * Loops;
@@ -150,39 +154,54 @@ static void get_incr_amount(void * data, struct rc_instruction * inst,
rc_register_file file, unsigned int index, unsigned int mask)
{
struct count_inst * count_inst = data;
+ int amnt_src_index;
+ struct rc_opcode_info * opcode;
+ float amount;
+
if(file != RC_FILE_TEMPORARY ||
count_inst->Index != index ||
(1 << GET_SWZ(count_inst->Swz,0) != mask)){
return;
}
+ /* Find the index of the counter register. */
+ opcode = rc_get_opcode_info(inst->U.I.Opcode);
+ if(opcode->NumSrcRegs != 2){
+ count_inst->Unknown = 1;
+ return;
+ }
+ if(inst->U.I.SrcReg[0].File == RC_FILE_TEMPORARY &&
+ inst->U.I.SrcReg[0].Index == count_inst->Index &&
+ inst->U.I.SrcReg[0].Swizzle == count_inst->Swz){
+ amnt_src_index = 1;
+ } else if( inst->U.I.SrcReg[1].File == RC_FILE_TEMPORARY &&
+ inst->U.I.SrcReg[1].Index == count_inst->Index &&
+ inst->U.I.SrcReg[1].Swizzle == count_inst->Swz){
+ amnt_src_index = 0;
+ }
+ else{
+ count_inst->Unknown = 1;
+ return;
+ }
+ if(src_reg_is_immediate(&inst->U.I.SrcReg[amnt_src_index],
+ count_inst->C)){
+ amount = get_constant_value(count_inst->C,
+ &inst->U.I.SrcReg[amnt_src_index], 0);
+ }
+ else{
+ count_inst->Unknown = 1 ;
+ return;
+ }
switch(inst->U.I.Opcode){
- int incr_reg;
case RC_OPCODE_ADD:
- {
- if(inst->U.I.SrcReg[0].File == RC_FILE_TEMPORARY &&
- inst->U.I.SrcReg[0].Index == count_inst->Index &&
- inst->U.I.SrcReg[0].Swizzle == count_inst->Swz){
- incr_reg = 1;
- } else if( inst->U.I.SrcReg[1].File == RC_FILE_TEMPORARY &&
- inst->U.I.SrcReg[1].Index == count_inst->Index &&
- inst->U.I.SrcReg[1].Swizzle == count_inst->Swz){
- incr_reg = 0;
- }
- else{
- count_inst->Unknown = 1;
- return;
- }
- if(src_reg_is_immediate(&inst->U.I.SrcReg[incr_reg],
- count_inst->C)){
- count_inst->Amount = get_constant_value(count_inst->C,
- &inst->U.I.SrcReg[incr_reg], 0);
- }
- else{
- count_inst->Unknown = 1 ;
+ count_inst->Amount += amount;
+ break;
+ case RC_OPCODE_SUB:
+ if(amnt_src_index == 0){
+ count_inst->Unknown = 0;
return;
}
+ count_inst->Amount -= amount;
break;
- }
default:
count_inst->Unknown = 1;
return;
@@ -192,7 +211,7 @@ static void get_incr_amount(void * data, struct rc_instruction * inst,
static int transform_const_loop(struct emulate_loop_state * s,
struct loop_info * loop,
- struct rc_instruction * slt)
+ struct rc_instruction * cond)
{
int end_loops = 1;
int iterations;
@@ -205,17 +224,16 @@ static int transform_const_loop(struct emulate_loop_state * s,
/* Find the counter and the upper limit */
- /* limit < counter */
- if(src_reg_is_immediate(&slt->U.I.SrcReg[0], s->C)){
- limit = &slt->U.I.SrcReg[0];
- counter = &slt->U.I.SrcReg[1];
+ if(src_reg_is_immediate(&cond->U.I.SrcReg[0], s->C)){
+ limit = &cond->U.I.SrcReg[0];
+ counter = &cond->U.I.SrcReg[1];
}
- /* counter < limit */
- else if(src_reg_is_immediate(&slt->U.I.SrcReg[1], s->C)){
- limit = &slt->U.I.SrcReg[1];
- counter = &slt->U.I.SrcReg[0];
+ else if(src_reg_is_immediate(&cond->U.I.SrcReg[1], s->C)){
+ limit = &cond->U.I.SrcReg[1];
+ counter = &cond->U.I.SrcReg[0];
}
else{
+ DBG("No constant limit.\n");
return 0;
}
@@ -229,9 +247,10 @@ static int transform_const_loop(struct emulate_loop_state * s,
rc_for_all_writes_mask(inst, update_const_value, &counter_value);
}
if(!counter_value.HasValue){
+ DBG("Initial counter value cannot be determined.\n");
return 0;
}
-
+ DBG("Initial counter value is %f\n", counter_value.Value);
/* Determine how the counter is modified each loop */
count_inst.C = s->C;
count_inst.Index = counter->Index;
@@ -249,6 +268,10 @@ static int transform_const_loop(struct emulate_loop_state * s,
loop->EndLoop = inst;
end_loops--;
break;
+ /* XXX Check if the counter is modified within an if statement.
+ */
+ case RC_OPCODE_IF:
+ break;
default:
rc_for_all_writes_mask(inst, get_incr_amount, &count_inst);
if(count_inst.Unknown){
@@ -257,23 +280,27 @@ static int transform_const_loop(struct emulate_loop_state * s,
break;
}
}
+ /* Infinite loop */
if(count_inst.Amount == 0.0f){
return 0;
}
-
- /* Calculate the number of iterations of this loop */
+ DBG("Counter is increased by %f each iteration.\n", count_inst.Amount);
+ /* Calculate the number of iterations of this loop. Keeping this
+ * simple, since we only support increment and decrement loops.
+ */
limit_value = get_constant_value(s->C, limit, 0);
iterations = (int) ((limit_value - counter_value.Value) /
count_inst.Amount);
+ DBG("Loop will have %d iterations.\n", iterations);
/* Prepare loop for unrolling */
/* Remove the first 4 instructions inside the loop, which are part
- * of the conditional and no longer needed(SGE, IF, BRK, ENDIF).
+ * of the conditional and no longer needed.
*/
- rc_remove_instruction(loop->BeginLoop->Next);
- rc_remove_instruction(loop->BeginLoop->Next);
- rc_remove_instruction(loop->BeginLoop->Next);
- rc_remove_instruction(loop->BeginLoop->Next);
+ rc_remove_instruction(loop->BeginLoop->Next); /* SLT/SGE */
+ rc_remove_instruction(loop->BeginLoop->Next); /* IF */
+ rc_remove_instruction(loop->BeginLoop->Next); /* BRK */
+ rc_remove_instruction(loop->BeginLoop->Next); /* ENDIF */
loop_unroll(s, loop, iterations);
loop->EndLoop = NULL;
@@ -283,13 +310,13 @@ static int transform_const_loop(struct emulate_loop_state * s,
/**
* This function prepares a loop to be unrolled by converting it into an if
* statement. Here is an outline of the conversion process:
- * BGNLOOP; -> BGNLOOP;
- * SGE temp[0], temp[1], temp[2]; -> SLT temp[0], temp[1], temp[2];
- * IF temp[0]; -> IF temp[0];
- * BRK; ->
- * ENDIF; -> <Loop Body>
- * <Loop Body> -> ENDIF;
- * ENDLOOP; -> ENDLOOP
+ * BGNLOOP; -> BGNLOOP;
+ * SGE/SLT temp[0], temp[1], temp[2]; -> SLT/SGE temp[0], temp[1], temp[2];
+ * IF temp[0]; -> IF temp[0];
+ * BRK; ->
+ * ENDIF; -> <Loop Body>
+ * <Loop Body> -> ENDIF;
+ * ENDLOOP; -> ENDLOOP
*
* @param inst A pointer to a BGNLOOP instruction.
* @return A pointer to the ENDLOOP instruction.
@@ -307,9 +334,16 @@ static struct rc_instruction * transform_loop(struct emulate_loop_state * s,
memset(loop, 0, sizeof(struct loop_info));
loop->BeginLoop = inst;
- /* Reverse the SGE instruction */
+ /* Reverse the conditional instruction */
ptr = inst->Next;
- ptr->U.I.Opcode = RC_OPCODE_SLT;
+ switch(ptr->U.I.Opcode){
+ case RC_OPCODE_SGE:
+ ptr->U.I.Opcode = RC_OPCODE_SLT;
+ break;
+ case RC_OPCODE_SLT:
+ ptr->U.I.Opcode = RC_OPCODE_SGE;
+ break;
+ }
/* Check if the number of loops is known at compile time. */
if(transform_const_loop(s, loop, ptr)){