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Another peephole optimization

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Wolfgang (Blub) Bumiller 2012-12-06 22:10:31 +01:00
parent 8858f265dd
commit c198c23df1
1 changed files with 90 additions and 39 deletions
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129
ir.c
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@ -546,49 +546,100 @@ bool ir_function_pass_peephole(ir_function *self)
size_t i; size_t i;
ir_block *block = self->blocks[b]; ir_block *block = self->blocks[b];
if (vec_size(block->instr) < 2) for (i = 0; i < vec_size(block->instr); ++i) {
continue; ir_instr *inst;
inst = block->instr[i];
for (i = 1; i < vec_size(block->instr); ++i) { if (i >= 1 &&
ir_instr *store; (inst->opcode >= INSTR_STORE_F &&
ir_instr *oper; inst->opcode <= INSTR_STORE_FNC))
ir_value *value;
store = block->instr[i];
if (store->opcode < INSTR_STORE_F ||
store->opcode > INSTR_STORE_FNC)
{ {
ir_instr *store;
ir_instr *oper;
ir_value *value;
store = inst;
oper = block->instr[i-1];
if (!instr_is_operation(oper->opcode))
continue;
value = oper->_ops[0];
/* only do it for SSA values */
if (value->store != store_value)
continue;
/* don't optimize out the temp if it's used later again */
if (vec_size(value->reads) != 1)
continue;
/* The very next store must use this value */
if (value->reads[0] != store)
continue;
/* And of course the store must _read_ from it, so it's in
* OP 1 */
if (store->_ops[1] != value)
continue;
++optimization_count[OPTIM_PEEPHOLE];
(void)!ir_instr_op(oper, 0, store->_ops[0], true);
vec_remove(block->instr, i, 1);
ir_instr_delete(store);
}
else if (inst->opcode == VINSTR_COND)
{
/* COND on a value resulting from a NOT could
* remove the NOT and swap its operands
*/
while (true) {
ir_block *tmp;
size_t inotid;
ir_instr *inot;
ir_value *value;
value = inst->_ops[0];
if (value->store != store_value ||
vec_size(value->reads) != 1 ||
value->reads[0] != inst)
{
break;
}
inot = value->writes[0];
if (inot->_ops[0] != value ||
inot->opcode < INSTR_NOT_F ||
inot->opcode > INSTR_NOT_FNC ||
inot->opcode == INSTR_NOT_V) /* can't do this one */
{
break;
}
/* count */
++optimization_count[OPTIM_PEEPHOLE];
/* change operand */
(void)!ir_instr_op(inst, 0, inot->_ops[1], false);
/* remove NOT */
tmp = inot->owner;
for (inotid = 0; inotid < vec_size(tmp->instr); ++inotid) {
if (tmp->instr[inotid] == inot)
break;
}
if (inotid >= vec_size(tmp->instr)) {
compile_error(inst->context, "sanity-check failed: failed to find instruction to optimize out");
return false;
}
vec_remove(tmp->instr, inotid, 1);
ir_instr_delete(inot);
/* swap ontrue/onfalse */
tmp = inst->bops[0];
inst->bops[0] = inst->bops[1];
inst->bops[1] = tmp;
}
continue; continue;
} }
oper = block->instr[i-1];
if (!instr_is_operation(oper->opcode))
continue;
value = oper->_ops[0];
/* only do it for SSA values */
if (value->store != store_value)
continue;
/* don't optimize out the temp if it's used later again */
if (vec_size(value->reads) != 1)
continue;
/* The very next store must use this value */
if (value->reads[0] != store)
continue;
/* And of course the store must _read_ from it, so it's in
* OP 1 */
if (store->_ops[1] != value)
continue;
++optimization_count[OPTIM_PEEPHOLE];
oper->_ops[0] = store->_ops[0];
vec_remove(block->instr, i, 1);
ir_instr_delete(store);
} }
} }