LiveRangeEdit::eliminateDeadDefs() can delete a dead instruction that
reads unreserved physregs. This would leave the corresponding regunit
live interval dangling because we don't have shrinkToUses() for physical
registers.
Fix this problem by turning the instruction into a KILL instead of
deleting it. This happens in a landing pad in
test/CodeGen/X86/2012-05-19-CoalescerCrash.ll:
%vreg27<def,dead> = COPY %EDX<kill>; GR32:%vreg27
becomes:
KILL %EDX<kill>
An upcoming fix to the machine verifier will catch problems like this by
verifying regunit live intervals.
This fixes PR13498. I am not including the test case from the PR since
we already have one exposing the problem once the verifier is fixed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161182 91177308-0d34-0410-b5e6-96231b3b80d8
LiveRangeEdit::foldAsLoad() can eliminate a register by folding a load
into its only use. Only do that when the load is safe to move, and it
won't extend any live ranges.
This fixes PR13414.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160575 91177308-0d34-0410-b5e6-96231b3b80d8
Also make sure registers aren't erased twice if the dead def mentions
the register twice.
This fixes PR12911.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157254 91177308-0d34-0410-b5e6-96231b3b80d8
Dead code elimination during coalescing could cause a virtual register
to be split into connected components. The following rewriting would be
confused about the already joined copies present in the code, but
without a corresponding value number in the live range.
Erase all joined copies instantly when joining intervals such that the
MI and LiveInterval representations are always in sync.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157135 91177308-0d34-0410-b5e6-96231b3b80d8
methods are no longer needed now that LinearScan has gone away.
(Contains tweaks trivialSpillEverywhere to enable the removal of getNewVRegs).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151658 91177308-0d34-0410-b5e6-96231b3b80d8
If we create new intervals for a variable that is being spilled, then those new intervals are not guaranteed to also spill. This means that anything reading from the original spilling value might not get the correct value if spills were missed.
Fixes <rdar://problem/10546864>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146428 91177308-0d34-0410-b5e6-96231b3b80d8
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.
For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146026 91177308-0d34-0410-b5e6-96231b3b80d8
The old naming scheme (load/use/def/store) can be traced back to an old
linear scan article, but the names don't match how slots are actually
used.
The load and store slots are not needed after the deferred spill code
insertion framework was deleted.
The use and def slots don't make any sense because we are using
half-open intervals as is customary in C code, but the names suggest
closed intervals. In reality, these slots were used to distinguish
early-clobber defs from normal defs.
The new naming scheme also has 4 slots, but the names match how the
slots are really used. This is a purely mechanical renaming, but some
of the code makes a lot more sense now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144503 91177308-0d34-0410-b5e6-96231b3b80d8
This function doesn't have anything to do with spill weights, and MRI
already has functions for manipulating the register class of a virtual
register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137123 91177308-0d34-0410-b5e6-96231b3b80d8
Remat during spilling triggers dead code elimination. If a phi-def
becomes unused, that may also cause live ranges to split into separate
connected components.
This type of splitting is different from normal live range splitting. In
particular, there may not be a common original interval.
When the split range is its own original, make sure that the new
siblings are also their own originals. The range being split cannot be
used as an original since it doesn't cover the new siblings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134413 91177308-0d34-0410-b5e6-96231b3b80d8
When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.
Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.
This fixes PR9823.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130687 91177308-0d34-0410-b5e6-96231b3b80d8
Jakob Stoklund Olesen
Pete Cooper
Lang Hames
Jim Grosbach
David Blaikie
Evan Cheng