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cfallincfallin
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Fix indent/conditional removal in #108 that removed wrong brace. (#111)
In #108, we had removed a conditional that became constant-false with the removal of pinned vregs. Unfortunately, in a pretty embarrassing text-editing error, I removed the wrong end-brace and re-indented. This had the effect of moving some of the move-resolution code around in the regalloc backend, skipping moves in some cases and generating incorrect results. Caught as a fuzzbug by OSS-Fuzz in [0] (public after this merges and is detected as fixed). [0]: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=55391
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‎src/ion/moves.rs

Lines changed: 81 additions & 81 deletions
Original file line numberDiff line numberDiff line change
@@ -364,101 +364,101 @@ impl<'a, F: Function> Env<'a, F> {
364364
}
365365

366366
block = block.next();
367+
}
367368

368-
// Scan over blocks whose beginnings are covered by
369-
// this range and for which the vreg is live at the
370-
// start of the block. For each, for each predecessor,
371-
// add a Dest half-move.
372-
let mut block = self.cfginfo.insn_block[range.from.inst().index()];
373-
if self.cfginfo.block_entry[block.index()] < range.from {
374-
block = block.next();
369+
// Scan over blocks whose beginnings are covered by
370+
// this range and for which the vreg is live at the
371+
// start of the block. For each, for each predecessor,
372+
// add a Dest half-move.
373+
let mut block = self.cfginfo.insn_block[range.from.inst().index()];
374+
if self.cfginfo.block_entry[block.index()] < range.from {
375+
block = block.next();
376+
}
377+
while block.is_valid() && block.index() < self.func.num_blocks() {
378+
if self.cfginfo.block_entry[block.index()] >= range.to {
379+
break;
375380
}
376-
while block.is_valid() && block.index() < self.func.num_blocks() {
377-
if self.cfginfo.block_entry[block.index()] >= range.to {
381+
382+
// Add half-moves for blockparam inputs.
383+
trace!(
384+
"scanning blockparam_ins at vreg {} block {}: blockparam_in_idx = {}",
385+
vreg.index(),
386+
block.index(),
387+
blockparam_in_idx
388+
);
389+
while blockparam_in_idx < self.blockparam_ins.len() {
390+
let BlockparamIn {
391+
from_block,
392+
to_block,
393+
to_vreg,
394+
} = self.blockparam_ins[blockparam_in_idx];
395+
if (to_vreg, to_block) > (vreg, block) {
378396
break;
379397
}
380-
381-
// Add half-moves for blockparam inputs.
382-
trace!(
383-
"scanning blockparam_ins at vreg {} block {}: blockparam_in_idx = {}",
384-
vreg.index(),
385-
block.index(),
386-
blockparam_in_idx
387-
);
388-
while blockparam_in_idx < self.blockparam_ins.len() {
389-
let BlockparamIn {
390-
from_block,
391-
to_block,
392-
to_vreg,
393-
} = self.blockparam_ins[blockparam_in_idx];
394-
if (to_vreg, to_block) > (vreg, block) {
395-
break;
396-
}
397-
if (to_vreg, to_block) == (vreg, block) {
398-
half_moves.push(HalfMove {
399-
key: half_move_key(
400-
from_block,
401-
to_block,
402-
to_vreg,
403-
HalfMoveKind::Dest,
398+
if (to_vreg, to_block) == (vreg, block) {
399+
half_moves.push(HalfMove {
400+
key: half_move_key(
401+
from_block,
402+
to_block,
403+
to_vreg,
404+
HalfMoveKind::Dest,
405+
),
406+
alloc,
407+
});
408+
trace!(
409+
"match: blockparam_in: v{} in block{} from block{} into {}",
410+
to_vreg.index(),
411+
to_block.index(),
412+
from_block.index(),
413+
alloc,
414+
);
415+
#[cfg(debug_assertions)]
416+
if self.annotations_enabled {
417+
self.annotate(
418+
self.cfginfo.block_entry[block.index()],
419+
format!(
420+
"blockparam-in: block{} to block{}:into v{} in {}",
421+
from_block.index(),
422+
to_block.index(),
423+
to_vreg.index(),
424+
alloc
404425
),
405-
alloc,
406-
});
407-
trace!(
408-
"match: blockparam_in: v{} in block{} from block{} into {}",
409-
to_vreg.index(),
410-
to_block.index(),
411-
from_block.index(),
412-
alloc,
413426
);
414-
#[cfg(debug_assertions)]
415-
if self.annotations_enabled {
416-
self.annotate(
417-
self.cfginfo.block_entry[block.index()],
418-
format!(
419-
"blockparam-in: block{} to block{}:into v{} in {}",
420-
from_block.index(),
421-
to_block.index(),
422-
to_vreg.index(),
423-
alloc
424-
),
425-
);
426-
}
427427
}
428-
blockparam_in_idx += 1;
429428
}
429+
blockparam_in_idx += 1;
430+
}
430431

431-
if !self.is_live_in(block, vreg) {
432-
block = block.next();
433-
continue;
434-
}
432+
if !self.is_live_in(block, vreg) {
433+
block = block.next();
434+
continue;
435+
}
436+
437+
trace!(
438+
"scanning preds at vreg {} block {} for ends outside the range",
439+
vreg.index(),
440+
block.index()
441+
);
435442

443+
// Now find any preds whose ends are not in the
444+
// same range, and insert appropriate moves.
445+
for &pred in self.func.block_preds(block) {
436446
trace!(
437-
"scanning preds at vreg {} block {} for ends outside the range",
438-
vreg.index(),
439-
block.index()
447+
"pred block {} has exit {:?}",
448+
pred.index(),
449+
self.cfginfo.block_exit[pred.index()]
440450
);
441-
442-
// Now find any preds whose ends are not in the
443-
// same range, and insert appropriate moves.
444-
for &pred in self.func.block_preds(block) {
445-
trace!(
446-
"pred block {} has exit {:?}",
447-
pred.index(),
448-
self.cfginfo.block_exit[pred.index()]
449-
);
450-
if range.contains_point(self.cfginfo.block_exit[pred.index()]) {
451-
continue;
452-
}
453-
trace!(" -> requires half-move");
454-
half_moves.push(HalfMove {
455-
key: half_move_key(pred, block, vreg, HalfMoveKind::Dest),
456-
alloc,
457-
});
451+
if range.contains_point(self.cfginfo.block_exit[pred.index()]) {
452+
continue;
458453
}
459-
460-
block = block.next();
454+
trace!(" -> requires half-move");
455+
half_moves.push(HalfMove {
456+
key: half_move_key(pred, block, vreg, HalfMoveKind::Dest),
457+
alloc,
458+
});
461459
}
460+
461+
block = block.next();
462462
}
463463

464464
// Scan over def/uses and apply allocations.

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