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Handle moves by joining LRs at inst boundary, not middle of move inst

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This commit is contained in:
Chris Fallin
2021-05-08 17:45:24 -07:00
parent 3d0d760c70
commit 00c64f680a
1 changed files with 68 additions and 59 deletions
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127
src/ion/mod.rs
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@@ -1301,69 +1301,78 @@ impl<'a, F: Function> Env<'a, F> {
// If this is a move, handle specially.
if let Some((src, dst)) = self.func.is_move(inst) {
log::debug!(" -> move inst{}: src {} -> dst {}", inst.index(), src, dst);
assert_eq!(src.class(), dst.class());
if src != dst {
log::debug!(" -> move inst{}: src {} -> dst {}", inst.index(), src, dst);
assert_eq!(src.class(), dst.class());
// Handle the def w.r.t. liveranges: trim the
// start of the range and mark it dead at this
// point in our backward scan.
let pos = ProgPoint::after(inst);
let mut dst_lr = vreg_ranges[dst.vreg()];
// If there was no liverange (dead def), create a trivial one.
if !live.get(dst.vreg()) {
dst_lr = self.add_liverange_to_vreg(
VRegIndex::new(dst.vreg()),
CodeRange {
from: pos,
to: pos.next(),
},
// Handle the def w.r.t. liveranges: trim the
// start of the range and mark it dead at this
// point in our backward scan.
let pos = ProgPoint::before(inst); // See note below re: pos of use.
let mut dst_lr = vreg_ranges[dst.vreg()];
// If there was no liverange (dead def), create a trivial one.
if !live.get(dst.vreg()) {
dst_lr = self.add_liverange_to_vreg(
VRegIndex::new(dst.vreg()),
CodeRange {
from: pos,
to: pos.next(),
},
&mut num_ranges,
);
log::debug!(" -> invalid; created {:?}", dst_lr);
} else {
log::debug!(" -> has existing LR {:?}", dst_lr);
}
if self.ranges_hot[dst_lr.index()].range.from
== self.cfginfo.block_entry[block.index()]
{
log::debug!(" -> started at block start; trimming to {:?}", pos);
self.ranges_hot[dst_lr.index()].range.from = pos;
}
live.set(dst.vreg(), false);
vreg_ranges[dst.vreg()] = LiveRangeIndex::invalid();
self.vreg_regs[dst.vreg()] = dst;
// Handle the use w.r.t. liveranges: make it live
// and create an initial LR back to the start of
// the block.
let pos = ProgPoint::before(inst);
let range = CodeRange {
from: self.cfginfo.block_entry[block.index()],
// Live up to end of previous inst. Because
// the move isn't actually reading the
// value as part of the inst, all we need
// to do is to decide where to join the
// LRs; and we want this to be at an inst
// boundary, not in the middle, so that
// the move-insertion logic remains happy.
to: pos,
};
let src_lr = self.add_liverange_to_vreg(
VRegIndex::new(src.vreg()),
range,
&mut num_ranges,
);
log::debug!(" -> invalid; created {:?}", dst_lr);
} else {
log::debug!(" -> has existing LR {:?}", dst_lr);
vreg_ranges[src.vreg()] = src_lr;
log::debug!(" -> src LR {:?}", src_lr);
// Add to live-set.
let src_is_dead_after_move = !live.get(src.vreg());
live.set(src.vreg(), true);
// Add to program-moves lists.
self.prog_move_srcs
.push(((VRegIndex::new(src.vreg()), inst), Allocation::none()));
self.prog_move_dsts
.push(((VRegIndex::new(dst.vreg()), inst), Allocation::none()));
if src_is_dead_after_move {
self.prog_move_merges.push((src_lr, dst_lr));
}
continue;
}
if self.ranges_hot[dst_lr.index()].range.from
== self.cfginfo.block_entry[block.index()]
{
log::debug!(" -> started at block start; trimming to {:?}", pos);
self.ranges_hot[dst_lr.index()].range.from = pos;
}
live.set(dst.vreg(), false);
vreg_ranges[dst.vreg()] = LiveRangeIndex::invalid();
self.vreg_regs[dst.vreg()] = dst;
// Handle the use w.r.t. liveranges: make it live
// and create an initial LR back to the start of
// the block.
let pos = ProgPoint::before(inst);
let range = CodeRange {
from: self.cfginfo.block_entry[block.index()],
to: pos.next(),
};
let src_lr = self.add_liverange_to_vreg(
VRegIndex::new(src.vreg()),
range,
&mut num_ranges,
);
vreg_ranges[src.vreg()] = src_lr;
log::debug!(" -> src LR {:?}", src_lr);
// Add to live-set.
let src_is_dead_after_move = !live.get(src.vreg());
live.set(src.vreg(), true);
// Add to program-moves lists.
self.prog_move_srcs
.push(((VRegIndex::new(src.vreg()), inst), Allocation::none()));
self.prog_move_dsts
.push(((VRegIndex::new(dst.vreg()), inst), Allocation::none()));
if src_is_dead_after_move {
self.prog_move_merges.push((src_lr, dst_lr));
}
continue;
}
// Process defs and uses.