From: Tom Stellard Date: Sat, 5 Jun 2010 19:59:02 +0000 (-0700) Subject: r300/compiler: Unroll loops that decrement the counter. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6f1b6814bcaeb375a15277547376b0f909a52123;p=mesa.git r300/compiler: Unroll loops that decrement the counter. e.g. for(i=10; i>0; i--) --- 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 21a9f31a66a..859023a4d8b 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; -> - * -> 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; -> + * -> 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)){