bjoernager/rust
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Extract remove_unused_stack_addr_and_stack_load

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This commit is contained in:
bjorn3 2019-12-27 16:37:49 +01:00
parent a8daa7115e
commit 943b81bb40
1 changed files with 56 additions and 49 deletions
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105
src/optimize/stack2reg.rs
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@ -37,9 +37,7 @@ pub(super) fn optimize_function(
) {
combine_stack_addr_with_load_store(func);
// Record all stack_addr, stack_load and stack_store instructions. Also record all stack_addr
// and stack_load insts whose result is used.
let mut stack_addr_load_insts_users = HashMap::<Inst, HashSet<Inst>>::new();
// Record all stack_addr, stack_load and stack_store instructions.
let mut stack_slot_usage_map = BTreeMap::<OrdStackSlot, StackSlotUsage>::new();
let mut cursor = FuncCursor::new(func);
@ -70,56 +68,12 @@ pub(super) fn optimize_function(
}
_ => {}
}
for &arg in cursor.func.dfg.inst_args(inst) {
if let ValueDef::Result(arg_origin, 0) = cursor.func.dfg.value_def(arg) {
match cursor.func.dfg[arg_origin].opcode() {
Opcode::StackAddr | Opcode::StackLoad => {
stack_addr_load_insts_users.entry(arg_origin).or_insert_with(HashSet::new).insert(inst);
}
_ => {}
}
}
}
}
}
println!(
"{}:\nstack_addr/stack_load users: {:?}\nstack slot usage: {:?}",
name,
stack_addr_load_insts_users,
stack_slot_usage_map,
);
println!("{}:\nstack slot usage: {:?}", name, stack_slot_usage_map);
for inst in stack_addr_load_insts_users.keys() {
let mut is_recorded_stack_addr_or_stack_load = false;
for stack_slot_users in stack_slot_usage_map.values() {
is_recorded_stack_addr_or_stack_load |= stack_slot_users.stack_addr.contains(inst) || stack_slot_users.stack_load.contains(inst);
}
assert!(is_recorded_stack_addr_or_stack_load);
}
// Replace all unused stack_addr and stack_load instructions with nop.
for stack_slot_users in stack_slot_usage_map.values_mut() {
// FIXME remove clone
for &inst in stack_slot_users.stack_addr.clone().iter() {
if stack_addr_load_insts_users.get(&inst).map(|users| users.is_empty()).unwrap_or(true) {
println!("Removing unused stack_addr {}", inst);
func.dfg.detach_results(inst);
func.dfg.replace(inst).nop();
stack_slot_users.stack_addr.remove(&inst);
}
}
for &inst in stack_slot_users.stack_load.clone().iter() {
if stack_addr_load_insts_users.get(&inst).map(|users| users.is_empty()).unwrap_or(true) {
println!("Removing unused stack_addr {}", inst);
func.dfg.detach_results(inst);
func.dfg.replace(inst).nop();
stack_slot_users.stack_load.remove(&inst);
}
}
}
remove_unused_stack_addr_and_stack_load(func, &mut stack_slot_usage_map);
println!("stack slot usage (after): {:?}", stack_slot_usage_map);
@ -175,6 +129,59 @@ fn combine_stack_addr_with_load_store(func: &mut Function) {
}
}
fn remove_unused_stack_addr_and_stack_load(func: &mut Function, stack_slot_usage_map: &mut BTreeMap<OrdStackSlot, StackSlotUsage>) {
// FIXME incrementally rebuild on each call?
let mut stack_addr_load_insts_users = HashMap::<Inst, HashSet<Inst>>::new();
let mut cursor = FuncCursor::new(func);
while let Some(_ebb) = cursor.next_ebb() {
while let Some(inst) = cursor.next_inst() {
for &arg in cursor.func.dfg.inst_args(inst) {
if let ValueDef::Result(arg_origin, 0) = cursor.func.dfg.value_def(arg) {
match cursor.func.dfg[arg_origin].opcode() {
Opcode::StackAddr | Opcode::StackLoad => {
stack_addr_load_insts_users.entry(arg_origin).or_insert_with(HashSet::new).insert(inst);
}
_ => {}
}
}
}
}
}
println!("stack_addr/stack_load users: {:?}", stack_addr_load_insts_users);
for inst in stack_addr_load_insts_users.keys() {
let mut is_recorded_stack_addr_or_stack_load = false;
for stack_slot_users in stack_slot_usage_map.values() {
is_recorded_stack_addr_or_stack_load |= stack_slot_users.stack_addr.contains(inst) || stack_slot_users.stack_load.contains(inst);
}
assert!(is_recorded_stack_addr_or_stack_load);
}
// Replace all unused stack_addr and stack_load instructions with nop.
for stack_slot_users in stack_slot_usage_map.values_mut() {
// FIXME remove clone
for &inst in stack_slot_users.stack_addr.clone().iter() {
if stack_addr_load_insts_users.get(&inst).map(|users| users.is_empty()).unwrap_or(true) {
println!("Removing unused stack_addr {}", inst);
func.dfg.detach_results(inst);
func.dfg.replace(inst).nop();
stack_slot_users.stack_addr.remove(&inst);
}
}
for &inst in stack_slot_users.stack_load.clone().iter() {
if stack_addr_load_insts_users.get(&inst).map(|users| users.is_empty()).unwrap_or(true) {
println!("Removing unused stack_addr {}", inst);
func.dfg.detach_results(inst);
func.dfg.replace(inst).nop();
stack_slot_users.stack_load.remove(&inst);
}
}
}
}
fn try_get_stack_slot_and_offset_for_addr(func: &Function, addr: Value) -> Option<(StackSlot, Offset32)> {
if let ValueDef::Result(addr_inst, 0) = func.dfg.value_def(addr) {
if let InstructionData::StackLoad {