static bool FreeUselessIns( block *tail, bool just_the_loop,
bool in_regalloc )
/***********************************************************************
Free any instructions which have not been marked
with the INS_VISITED bit. See below for the setting
of this bit.
*/
{
block *blk;
instruction *ins;
instruction *prev;
bool change;
change = FALSE;
for( blk = tail; blk != NULL; blk = blk->prev_block ) {
if( just_the_loop && !( blk->class & IN_LOOP ) ) {
for( ins = blk->ins.hd.prev; ins->head.opcode != OP_BLOCK; ins = ins->head.prev ) {
ins->ins_flags &= ~INS_VISITED;
}
} else {
for( ins = blk->ins.hd.prev; ins->head.opcode != OP_BLOCK; ins = prev ) {
prev = ins->head.prev;
if( ( ins->ins_flags & INS_VISITED ) == 0 ) {
change = TRUE;
if( in_regalloc ) {
DoNothing( ins );
} else {
FreeIns( ins );
}
} else {
ins->ins_flags &= ~INS_VISITED;
}
}
}
}
bool ScConvert( instruction *ins )
/********************************************
Get rid of instructions like CBW if the high part is not used in the
next instruction.
*/
{
hw_reg_set tmp;
if( G( ins ) == G_SIGNEX ) {
tmp = HighReg( ins->result->r.reg );
if( !HW_Ovlap( ins->head.next->head.live.regs, tmp ) ) {
FreeIns( ins ); /* get rid of the pesky cwd or cbw instruction!*/
return( true );
}
}
return( false );
}
void FreeJunk( block *blk )
/*************************************
Free instructions which aren't going to be generated.
*/
{
instruction *ins;
instruction *next;
for( ins = blk->ins.hd.next; ins->head.opcode != OP_BLOCK; ins = next ) {
next = ins->head.next;
if( !DoesSomething( ins ) && !SideEffect( ins )
&& ins->head.opcode < FIRST_OP_WITH_LABEL
&& ins->head.opcode != OP_NOP ) { /*% there for zap info*/
FreeIns( ins );
}
}
}
void RemoveBlock( block *blk )
/*******************************/
{
block_num i;
unsigned last_line;
block *chk;
block *next;
instruction *next_ins;
if( blk->prev_block != NULL ) {
blk->prev_block->next_block = blk->next_block;
}
if( blk->next_block != NULL ) {
blk->next_block->prev_block = blk->prev_block;
}
for( i = 0; i < blk->targets; ++i ) {
/* block may have already been removed by dead code removal*/
if( FindBlock( blk->edge[i].destination.u.blk ) ) {
RemoveInputEdge( & blk->edge[i] );
}
}
last_line = blk->ins.hd.line_num;
for( ;; ) {
next_ins = blk->ins.hd.next;
if( next_ins == (instruction *)&blk->ins ) break;
if( next_ins->head.line_num != 0 ) {
last_line = next_ins->head.line_num;
}
FreeIns( next_ins );
}
/*
Move the last line number from the block being deleted to the head
of the next block in source order, if that block doesn't already
have a line number on it.
*/
if( blk->next_block != NULL && blk->next_block->gen_id == (blk->gen_id + 1) ) {
/* quick check to see if following block is next one in src order */
next = blk->next_block;
} else {
next = NULL;
for( chk = HeadBlock; chk != NULL; chk = chk->next_block ) {
if( (chk != blk)
&& (chk->gen_id > blk->gen_id)
&& (next == NULL || next->gen_id > chk->gen_id) ) {
next = chk;
}
}
}
if( next != NULL && next->ins.hd.line_num == 0 ) {
next->ins.hd.line_num = last_line;
}
if( HeadBlock == blk ) {
HeadBlock = blk->next_block;
}
if( BlockList == blk ) {
BlockList = blk->prev_block;
if( BlockList == NULL ) {
BlockList = HeadBlock;
}
}
TellScrapLabel( blk->label );
if( blk->dataflow != NULL ) {
CGFree( blk->dataflow );
}
FreeABlock( blk );
}
