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/*
* Copyright 2010 Tom Stellard <tstellar@gmail.com>
*
* All Rights Reserved.
*
* 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 COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS 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
*/
#include "radeon_emulate_loops.h"
#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;
unsigned int LoopCount;
unsigned int LoopReserved;
};
struct loop_info {
struct rc_instruction * BeginLoop;
struct rc_instruction * EndLoop;
};
struct const_value {
struct radeon_compiler * C;
struct rc_src_register * Src;
float Value;
int HasValue;
};
struct count_inst {
struct radeon_compiler * C;
int Index;
rc_swizzle Swz;
float Amount;
int Unknown;
};
static float get_constant_value(struct radeon_compiler * c,
struct rc_src_register * src,
int chan)
{
float base = 1.0f;
int swz = GET_SWZ(src->Swizzle, chan);
if(swz >= 4 || src->Index >= c->Program.Constants.Count ){
rc_error(c, "get_constant_value: Can't find a value.\n");
return 0.0f;
}
if(GET_BIT(src->Negate, chan)){
base = -1.0f;
}
return base *
c->Program.Constants.Constants[src->Index].u.Immediate[swz];
}
static int src_reg_is_immediate(struct rc_src_register * src,
struct radeon_compiler * c)
{
return src->File == RC_FILE_CONSTANT &&
c->Program.Constants.Constants[src->Index].Type==RC_CONSTANT_IMMEDIATE;
}
static unsigned int loop_count_instructions(struct loop_info * loop)
{
unsigned int count = 0;
struct rc_instruction * inst = loop->BeginLoop->Next;
while(inst != loop->EndLoop){
count++;
inst = inst->Next;
}
return count;
}
static unsigned int loop_calc_iterations(struct loop_info * loop,
unsigned int loop_count, unsigned int max_instructions)
{
unsigned int icount = loop_count_instructions(loop);
return max_instructions / (loop_count * icount);
}
static void loop_unroll(struct emulate_loop_state * s,
struct loop_info *loop, unsigned int iterations)
{
unsigned int i;
struct rc_instruction * ptr;
struct rc_instruction * first = loop->BeginLoop->Next;
struct rc_instruction * last = loop->EndLoop->Prev;
struct rc_instruction * append_to = last;
rc_remove_instruction(loop->BeginLoop);
rc_remove_instruction(loop->EndLoop);
for( i = 1; i < iterations; i++){
for(ptr = first; ptr != last->Next; ptr = ptr->Next){
struct rc_instruction *new = rc_alloc_instruction(s->C);
memcpy(new, ptr, sizeof(struct rc_instruction));
rc_insert_instruction(append_to, new);
append_to = new;
}
}
}
static void update_const_value(void * data, struct rc_instruction * inst,
rc_register_file file, unsigned int index, unsigned int mask)
{
struct const_value * value = data;
if(value->Src->File != file ||
value->Src->Index != index ||
!(1 << GET_SWZ(value->Src->Swizzle, 0) & mask)){
return;
}
switch(inst->U.I.Opcode){
case RC_OPCODE_MOV:
if(!src_reg_is_immediate(&inst->U.I.SrcReg[0], value->C)){
return;
}
value->HasValue = 1;
value->Value =
get_constant_value(value->C, &inst->U.I.SrcReg[0], 0);
break;
}
}
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){
case RC_OPCODE_ADD:
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;
}
}
static int transform_const_loop(struct emulate_loop_state * s,
struct loop_info * loop,
struct rc_instruction * cond)
{
int end_loops = 1;
int iterations;
struct count_inst count_inst;
float limit_value;
struct rc_src_register * counter;
struct rc_src_register * limit;
struct const_value counter_value;
struct rc_instruction * inst;
/* Find the counter and the upper limit */
if(src_reg_is_immediate(&cond->U.I.SrcReg[0], s->C)){
limit = &cond->U.I.SrcReg[0];
counter = &cond->U.I.SrcReg[1];
}
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;
}
/* Find the initial value of the counter */
counter_value.Src = counter;
counter_value.Value = 0.0f;
counter_value.HasValue = 0;
counter_value.C = s->C;
for(inst = s->C->Program.Instructions.Next; inst != loop->BeginLoop;
inst = inst->Next){
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;
count_inst.Swz = counter->Swizzle;
count_inst.Amount = 0.0f;
count_inst.Unknown = 0;
for(inst = loop->BeginLoop->Next; end_loops > 0; inst = inst->Next){
switch(inst->U.I.Opcode){
/* XXX In the future we might want to try to unroll nested
* loops here.*/
case RC_OPCODE_BGNLOOP:
end_loops++;
break;
case RC_OPCODE_ENDLOOP:
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){
return 0;
}
break;
}
}
/* Infinite loop */
if(count_inst.Amount == 0.0f){
return 0;
}
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.
*/
/* SLT/SGE/SGT/SLE */
if(loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_SLT &&
loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_SGE &&
loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_SGT &&
loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_SLE){
rc_error(s->C,"Unexpected instruction, expected LT,GT,LE,GE\n");
return 0;
}
/* IF */
rc_remove_instruction(loop->BeginLoop->Next);
if(loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_IF){
rc_error(s->C,"Unexpected instruction, expected IF\n");
return 0;
}
rc_remove_instruction(loop->BeginLoop->Next);
/* BRK */
if(loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_BRK){
rc_error(s->C,"Unexpected instruction, expected BRK\n");
return 0;
}
rc_remove_instruction(loop->BeginLoop->Next);
/* ENDIF */
if(loop->BeginLoop->Next->U.I.Opcode != RC_OPCODE_ENDIF){
rc_error(s->C,"Unexpected instruction, expected ENDIF\n");
return 0;
}
rc_remove_instruction(loop->BeginLoop->Next);
loop_unroll(s, loop, iterations);
loop->EndLoop = NULL;
return 1;
}
/**
* 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/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.
*/
static struct rc_instruction * transform_loop(struct emulate_loop_state * s,
struct rc_instruction * inst)
{
struct loop_info *loop;
struct rc_instruction * ptr;
memory_pool_array_reserve(&s->C->Pool, struct loop_info,
s->Loops, s->LoopCount, s->LoopReserved, 1);
loop = &s->Loops[s->LoopCount++];
memset(loop, 0, sizeof(struct loop_info));
loop->BeginLoop = inst;
/* Reverse the conditional instruction */
ptr = inst->Next;
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;
case RC_OPCODE_SLE:
ptr->U.I.Opcode = RC_OPCODE_SGT;
break;
case RC_OPCODE_SGT:
ptr->U.I.Opcode = RC_OPCODE_SLE;
break;
default:
rc_error(s->C,
"Loop does not start with a conditional instruction.");
break;
}
/* Check if the number of loops is known at compile time. */
if(transform_const_loop(s, loop, ptr)){
return loop->BeginLoop->Next;
}
while(!loop->EndLoop){
struct rc_instruction * endif;
if(ptr->Type == RC_INSTRUCTION_NORMAL){
}
switch(ptr->U.I.Opcode){
case RC_OPCODE_BGNLOOP:
/* Nested loop */
ptr = transform_loop(s, ptr);
break;
case RC_OPCODE_BRK:
/* The BRK instruction should always be followed by
* an ENDIF. This ENDIF will eventually replace the
* ENDLOOP insruction. */
if(ptr->Next->U.I.Opcode != RC_OPCODE_ENDIF){
rc_error(s->C,
"transform_loop: expected ENDIF\n");
}
endif = ptr->Next;
rc_remove_instruction(ptr);
rc_remove_instruction(endif);
break;
case RC_OPCODE_ENDLOOP:
/* Insert the ENDIF before ENDLOOP. */
rc_insert_instruction(ptr->Prev, endif);
loop->EndLoop = ptr;
break;
}
ptr = ptr->Next;
}
return ptr;
}
static void rc_transform_loops(struct emulate_loop_state * s)
{
struct rc_instruction * ptr = s->C->Program.Instructions.Next;
while(ptr != &s->C->Program.Instructions) {
if(ptr->Type == RC_INSTRUCTION_NORMAL &&
ptr->U.I.Opcode == RC_OPCODE_BGNLOOP){
ptr = transform_loop(s, ptr);
}
ptr = ptr->Next;
}
}
static void rc_unroll_loops(struct emulate_loop_state *s,
unsigned int max_instructions)
{
int i;
/* Iterate backwards of the list of loops so that loops that nested
* loops are unrolled first.
*/
for( i = s->LoopCount - 1; i >= 0; i-- ){
if(!s->Loops[i].EndLoop){
continue;
}
unsigned int iterations = loop_calc_iterations(&s->Loops[i],
s->LoopCount, max_instructions);
loop_unroll(s, &s->Loops[i], iterations);
}
}
void rc_emulate_loops(struct radeon_compiler *c, unsigned int max_instructions)
{
struct emulate_loop_state s;
memset(&s, 0, sizeof(struct emulate_loop_state));
s.C = c;
/* We may need to move these two operations to r3xx_(vert|frag)prog.c
* and run the optimization passes between them in order to increase
* the number of unrolls we can do for each loop.
*/
rc_transform_loops(&s);
rc_unroll_loops(&s, max_instructions);
}
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