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Replace some uses of layout::Cursor with FuncCursor.

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The layout::Cursor is unfortunate because it doesn't reference the whole
function.
This commit is contained in:
Jakob Stoklund Olesen
2017-09-21 11:21:23 -07:00
parent ed6630dc02
commit 03dee5e442
3 changed files with 31 additions and 32 deletions
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25
lib/cretonne/src/simple_gvn.rs
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@@ -1,8 +1,9 @@
//! A simple GVN pass.
use cursor::{Cursor, FuncCursor};
use flowgraph::ControlFlowGraph;
use dominator_tree::DominatorTree;
use ir::{Cursor, CursorBase, InstructionData, Function, Inst, Opcode, Type};
use ir::{InstructionData, Function, Inst, Opcode, Type};
use scoped_hash_map::ScopedHashMap;
/// Test whether the given opcode is unsafe to even consider for GVN.
@@ -22,13 +23,13 @@ pub fn do_simple_gvn(func: &mut Function, cfg: &mut ControlFlowGraph, domtree: &
let mut scope_stack: Vec<Inst> = Vec::new();
// Visit EBBs in a reverse post-order.
let mut pos = Cursor::new(&mut func.layout);
let mut pos = FuncCursor::new(func);
for &ebb in domtree.cfg_postorder().iter().rev() {
// Pop any scopes that we just exited.
loop {
if let Some(current) = scope_stack.last() {
if domtree.dominates(*current, ebb, &pos.layout) {
if domtree.dominates(*current, ebb, &pos.func.layout) {
break;
}
} else {
@@ -39,38 +40,38 @@ pub fn do_simple_gvn(func: &mut Function, cfg: &mut ControlFlowGraph, domtree: &
}
// Push a scope for the current block.
scope_stack.push(pos.layout.first_inst(ebb).unwrap());
scope_stack.push(pos.func.layout.first_inst(ebb).unwrap());
visible_values.increment_depth();
pos.goto_top(ebb);
while let Some(inst) = pos.next_inst() {
// Resolve aliases, particularly aliases we created earlier.
func.dfg.resolve_aliases_in_arguments(inst);
pos.func.dfg.resolve_aliases_in_arguments(inst);
let opcode = func.dfg[inst].opcode();
let opcode = pos.func.dfg[inst].opcode();
if opcode.is_branch() && !opcode.is_terminator() {
scope_stack.push(pos.layout.next_inst(inst).unwrap());
scope_stack.push(pos.func.layout.next_inst(inst).unwrap());
visible_values.increment_depth();
}
if trivially_unsafe_for_gvn(opcode) {
continue;
}
let ctrl_typevar = func.dfg.ctrl_typevar(inst);
let key = (func.dfg[inst].clone(), ctrl_typevar);
let ctrl_typevar = pos.func.dfg.ctrl_typevar(inst);
let key = (pos.func.dfg[inst].clone(), ctrl_typevar);
let entry = visible_values.entry(key);
use scoped_hash_map::Entry::*;
match entry {
Occupied(entry) => {
debug_assert!(domtree.dominates(*entry.get(), inst, pos.layout));
debug_assert!(domtree.dominates(*entry.get(), inst, &pos.func.layout));
// If the redundant instruction is representing the current
// scope, pick a new representative.
let old = scope_stack.last_mut().unwrap();
if *old == inst {
*old = pos.layout.next_inst(inst).unwrap();
*old = pos.func.layout.next_inst(inst).unwrap();
}
// Replace the redundant instruction and remove it.
func.dfg.replace_with_aliases(inst, *entry.get());
pos.func.dfg.replace_with_aliases(inst, *entry.get());
pos.remove_inst_and_step_back();
}
Vacant(entry) => {