of the copy is a subregister def. The current code assumes that it can do a full
def of the destination register, but it is not checking that the def operand is
read-undef. It also doesn't clear the subregister index of the destination in
the new instruction to reflect the full subregister def.
These issues were found running 'make check' with my next commit that enables
rematerialization in more cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175122 91177308-0d34-0410-b5e6-96231b3b80d8
RegisterCoalescer used to depend on LiveDebugVariable. LDV removes DBG_VALUEs
without emitting them at the end.
We fix this by removing LDV from RegisterCoalescer. Also add an assertion to
make sure we call emitDebugValues if DBG_VALUEs are removed at
runOnMachineFunction.
rdar://problem/13183203
Reviewed by Andy & Jakob
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175023 91177308-0d34-0410-b5e6-96231b3b80d8
Most IMPLICIT_DEF instructions are removed by the ProcessImplicitDefs
pass, and a few are reinserted by PHIElimination when a PHI argument is
<undef>.
RegisterCoalescer was assuming that all IMPLICIT_DEF live ranges look
like those created by PHIElimination, and that their live range never
leaves the basic block.
The PR14732 test case does tricks with PHI nodes that causes a longer
IMPLICIT_DEF live range to appear. This happens very rarely, but
RegisterCoalescer should be able to handle it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171435 91177308-0d34-0410-b5e6-96231b3b80d8
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.
There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.
The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.
I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).
I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
This could cause miscompilations in targets where sub-register
composition is not always idempotent (ARM).
<rdar://problem/12758887>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168837 91177308-0d34-0410-b5e6-96231b3b80d8
No functional change, just moved header files.
Targets can inject custom passes between register allocation and
rewriting. This makes it possible to tweak the register allocation
before rewriting, using the full global interference checking available
from LiveRegMatrix.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168806 91177308-0d34-0410-b5e6-96231b3b80d8
Jakub Staszak spotted this in review. I don't notice these things
until I manually rerun benchmarks. But reducing unit tests is a very
high priority.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168021 91177308-0d34-0410-b5e6-96231b3b80d8
This option will eventually either be enabled unconditionally or
replaced by a more general live range splitting optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167879 91177308-0d34-0410-b5e6-96231b3b80d8
This allows me to begin enabling (or backing out) misched by default
for one subtarget at a time. To run misched we typically want to:
- Disable SelectionDAG scheduling (use the source order scheduler)
- Enable more aggressive coalescing (until we decide to always run the coalescer this way)
- Enable MachineScheduler pass itself.
Disabling PostRA sched may follow for some subtargets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167826 91177308-0d34-0410-b5e6-96231b3b80d8
This adds the -join-globalcopies option which can be enabled by
default once misched is also enabled.
Ideally, the register coalescer would be able to split local live
ranges in a way that produces copies that can be easily resolved by
the scheduler. Until then, this heuristic should be good enough to at
least allow the scheduler to run after coalescing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167825 91177308-0d34-0410-b5e6-96231b3b80d8
This teaches the register coalescer to be less prone to split critical
edges. I am currently benchmarking this with the new (post-coalescer)
scheduler. I plan to enable this by default and remove the option as
soon as misched is enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167758 91177308-0d34-0410-b5e6-96231b3b80d8
Partial copies can show up even when CoalescerPair.isPartial() returns
false. For example:
%vreg24:dsub_0<def> = COPY %vreg31:dsub_0; QPR:%vreg24,%vreg31
Such a partial-partial copy is not good enough for the transformation
adjustCopiesBackFrom() needs to do.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166944 91177308-0d34-0410-b5e6-96231b3b80d8
The new coalescer can merge a dead def into an unused lane of an
otherwise live vector register.
Clear the <dead> flag when that happens since the flag refers to the
full virtual register which is still live after the partial dead def.
This fixes PR14079.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165877 91177308-0d34-0410-b5e6-96231b3b80d8
PHIElimination inserts IMPLICIT_DEF instructions to guarantee that all
PHI predecessors have a live-out value. These IMPLICIT_DEF values are
not considered to be real interference when coalescing virtual
registers:
%vreg1 = IMPLICIT_DEF
%vreg2 = MOV32r0
When joining %vreg1 and %vreg2, the IMPLICIT_DEF instruction and its
value number should simply be erased since the %vreg2 value number now
provides a live-out value for the PHI predecesor block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165813 91177308-0d34-0410-b5e6-96231b3b80d8
JoinVals::pruneValues() calls LIS->pruneValue() to avoid conflicts when
overlapping two different values. This produces a set of live range end
points that are used to reconstruct the live range (with SSA update)
after joining the two registers.
When a value is pruned twice, the set of end points was insufficient:
v1 = DEF
v1 = REPLACE1
v1 = REPLACE2
KILL v1
The end point at KILL would only reconstruct the live range from
REPLACE2 to KILL, leaving the range REPLACE1-REPLACE2 dead.
Add REPLACE2 as an end point in this case so the full live range is
reconstructed.
This fixes PR13999.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165056 91177308-0d34-0410-b5e6-96231b3b80d8
The new coalescer can turn a full virtual register definition into a
partial redef by merging another value into an unused vector lane.
Make sure to clear the <read-undef> flag on such defs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164807 91177308-0d34-0410-b5e6-96231b3b80d8
A PHI can't create interference on its own. If two live ranges interfere
at a PHI, they must also interfere when leaving one of the PHI
predecessors.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164330 91177308-0d34-0410-b5e6-96231b3b80d8
The old-fashioned many-to-one value mapping doesn't always work when
merging vector lanes. A value can map to multiple different values, and
it can even be necessary to insert new PHIs.
When a value number is defined by a copy from a value number that
required SSa update, include the live range of the copied value number
in the SSA update as well. It is not necessarily a copy of the original
value number any longer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164329 91177308-0d34-0410-b5e6-96231b3b80d8
A common coalescing conflict in vector code is lane insertion:
%dst = FOO
%src = BAR
%dst:ssub0 = COPY %src
The live range of %src interferes with the ssub0 lane of %dst, but that
lane is never read after %src would have clobbered it. That makes it
safe to merge the live ranges and eliminate the COPY:
%dst = FOO
%dst:ssub0 = BAR
This patch teaches the new coalescer to resolve conflicts where dead
vector lanes would be clobbered, at least as long as the clobbered
vector lanes don't escape the basic block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164250 91177308-0d34-0410-b5e6-96231b3b80d8
Add LIS::pruneValue() and extendToIndices(). These two functions are
used by the register coalescer when merging two live ranges requires
more than a trivial value mapping as supported by LiveInterval::join().
The pruneValue() function can remove the part of a value number that is
going to conflict in join(). Afterwards, extendToIndices can restore the
live range, using any new dominating value numbers and updating the SSA
form.
Use this complex value mapping to support merging a register into a
vector lane that has a conflicting value, but the clobbered lane is
undef.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164074 91177308-0d34-0410-b5e6-96231b3b80d8
The live range of an SSA value forms a sub-tree of the dominator tree.
That means the live ranges of two values overlap if and only if the def
of one value lies within the live range of the other.
This can be used to simplify the interference checking a bit: Visit each
def in the two registers about to be joined. Check for interference
against the value that is live in the other register at the def point
only. It is not necessary to scan the set of overlapping live ranges,
this interference check can be done while computing the value mapping
required for the final live range join.
The new algorithm is prepared to handle more complicated conflict
resolution - We can allow overlapping live ranges with different values
as long as the differing lanes are undef or unused in the other
register.
The implementation in this patch doesn't do that yet, it creates code
that is nearly identical to the old algorithm's, except:
- The new stripCopies() function sees through multiple copies while
the old RegistersDefinedFromSameValue() only can handle one.
- There are a few rare cases where the new algorithm can erase an
IMPLICIT_DEF instuction that RegistersDefinedFromSameValue() couldn't
handle.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163991 91177308-0d34-0410-b5e6-96231b3b80d8
Kill flags are removed more and more aggressively during the register
allocation passes, it is better to get information from LiveIntervals.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163972 91177308-0d34-0410-b5e6-96231b3b80d8
Based on CR feedback from r162301 and Craig Topper's refactoring in r162347
here are a few other places that could use the same API (& in one instance drop
a Function.h dependency).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162367 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, the identity copy would survive through register allocation
before it was removed by the rewriter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161269 91177308-0d34-0410-b5e6-96231b3b80d8
The only real user of the flag was removeCopyByCommutingDef(), and it
has been switched to LiveIntervals::hasPHIKill().
All the code changed by this patch was only concerned with computing and
propagating the flag.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161255 91177308-0d34-0410-b5e6-96231b3b80d8
The VNInfo::HAS_PHI_KILL is only half supported. We precompute it in
LiveIntervalAnalysis, but it isn't properly updated by live range
splitting and functions like shrinkToUses().
It is only used in one place: RegisterCoalescer::removeCopyByCommutingDef().
This patch changes that function to use a new LiveIntervals::hasPHIKill()
function that computes the flag for a given value number.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161254 91177308-0d34-0410-b5e6-96231b3b80d8
We are extending live ranges, so kill flags are not accurate. They
aren't needed until they are recomputed after RA anyway.
<rdar://problem/11950722>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161023 91177308-0d34-0410-b5e6-96231b3b80d8
implicit_def, the other instruction can be anything, including instructions
that define multiple values. Be careful about that and don't assume what operand
0 is.
Fixes pr13249.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159509 91177308-0d34-0410-b5e6-96231b3b80d8
