Commit Graph

76 Commits

Author SHA1 Message Date
Geoff Berry a2b9011290 Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Re-enable commit r323991 now that r325931 has been committed to make
MachineOperand::isRenamable() check more conservative w.r.t. code
changes and opt-in on a per-target basis.

llvm-svn: 326208
2018-02-27 16:59:10 +00:00
Quentin Colombet 48abac82b8 Revert "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
This reverts commit r323991.

This commit breaks target that don't model all the register constraints
in TableGen. So far the workaround was to set the
hasExtraXXXRegAllocReq, but it proves that it doesn't cover all the
cases.
For instance, when mutating an instruction (like in the lowering of
COPYs) the isRenamable flag is not properly updated. The same problem
will happen when attaching machine operand from one instruction to
another.

Geoff Berry is working on a fix in https://reviews.llvm.org/D43042.

llvm-svn: 325421
2018-02-17 03:05:33 +00:00
Geoff Berry 94503c7bc3 [MachineCopyPropagation] Extend pass to do COPY source forwarding
Summary:
This change extends MachineCopyPropagation to do COPY source forwarding
and adds an additional run of the pass to the default pass pipeline just
after register allocation.

This version of this patch uses the newly added
MachineOperand::isRenamable bit to avoid forwarding registers is such a
way as to violate constraints that aren't captured in the
Machine IR (e.g. ABI or ISA constraints).

This change is a continuation of the work started in D30751.

Reviewers: qcolombet, javed.absar, MatzeB, jonpa, tstellar

Subscribers: tpr, mgorny, mcrosier, nhaehnle, nemanjai, jyknight, hfinkel, arsenm, inouehrs, eraman, sdardis, guyblank, fedor.sergeev, aheejin, dschuff, jfb, myatsina, llvm-commits

Differential Revision: https://reviews.llvm.org/D41835

llvm-svn: 323991
2018-02-01 18:54:01 +00:00
Matthias Braun f1caa2833f MachineFunction: Return reference from getFunction(); NFC
The Function can never be nullptr so we can return a reference.

llvm-svn: 320884
2017-12-15 22:22:58 +00:00
Michael Zolotukhin c468b648fd Remove redundant includes from lib/CodeGen.
llvm-svn: 320619
2017-12-13 21:30:47 +00:00
Francis Visoiu Mistrih a8a83d150f [CodeGen] Use MachineOperand::print in the MIRPrinter for MO_Register.
Work towards the unification of MIR and debug output by refactoring the
interfaces.

For MachineOperand::print, keep a simple version that can be easily called
from `dump()`, and a more complex one which will be called from both the
MIRPrinter and MachineInstr::print.

Add extra checks inside MachineOperand for detached operands (operands
with getParent() == nullptr).

https://reviews.llvm.org/D40836

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+)<def> ([^ ]+)/kill: \1 def \2 \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/kill: def ([^ ]+) ([^ ]+) ([^ ]+)<def>/kill: def \1 \2 def \3/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/<def>//g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<kill>/killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use,kill>/implicit killed \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<def[ ]*,[ ]*dead>/dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def[ ]*,[ ]*dead>/implicit-def dead \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-def>/implicit-def \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<imp-use>/implicit \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<internal>/internal \1/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" -o -name "*.s" \) -type f -print0 | xargs -0 sed -i '' -E 's/([^ ]+)<undef>/undef \1/g'

llvm-svn: 320022
2017-12-07 10:40:31 +00:00
Francis Visoiu Mistrih 9d7bb0cb40 [CodeGen] Print register names in lowercase in both MIR and debug output
As part of the unification of the debug format and the MIR format,
always print registers as lowercase.

* Only debug printing is affected. It now follows MIR.

Differential Revision: https://reviews.llvm.org/D40417

llvm-svn: 319187
2017-11-28 17:15:09 +00:00
David Blaikie b3bde2ea50 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00
Alexander Timofeev 28da06778f [AMDGPU] Prevent Machine Copy Propagation from replacing live copy with the dead one
Differential revision: https://reviews.llvm.org/D38754

llvm-svn: 317884
2017-11-10 12:21:10 +00:00
David Blaikie 3f833edc7c Target/TargetInstrInfo.h -> CodeGen/TargetInstrInfo.h to match layering
This header includes CodeGen headers, and is not, itself, included by
any Target headers, so move it into CodeGen to match the layering of its
implementation.

llvm-svn: 317647
2017-11-08 01:01:31 +00:00
Alexander Timofeev 9dff31c769 [AMDGPU] : revert r315908
llvm-svn: 315916
2017-10-16 16:57:37 +00:00
Alexander Timofeev 3828242c7e [AMDGPU] Prevent Machine Copy Propagation from replacing live copy with the dead one
Differential revision: https://reviews.llvm.org/D38754

llvm-svn: 315908
2017-10-16 14:35:29 +00:00
Geoff Berry fabedbad11 Revert "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""
This reverts commit r314729.

Another bug has been encountered in an out-of-tree target reported by Quentin.

llvm-svn: 314814
2017-10-03 16:59:13 +00:00
Geoff Berry bfc5fb4571 Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues addressed since original review:
- Avoid bug in regalloc greedy/machine verifier when forwarding to use
  in an instruction that re-defines the same virtual register.
- Fixed bug when forwarding to use in EarlyClobber instruction slot.
- Fixed incorrect forwarding to register definitions that showed up in
  explicit_uses() iterator (e.g. in INLINEASM).
- Moved removal of dead instructions found by
  LiveIntervals::shrinkToUses() outside of loop iterating over
  instructions to avoid instructions being deleted while pointed to by
  iterator.
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
  doing so can break code that implicitly relies on the physical
  register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
  can break the machine verifier by creating LiveRanges that don't
  end on a use (since the undef operand is not considered a use).

  [MachineCopyPropagation] Extend pass to do COPY source forwarding

  This change extends MachineCopyPropagation to do COPY source forwarding.

  This change also extends the MachineCopyPropagation pass to be able to
  be run during register allocation, after physical registers have been
  assigned, but before the virtual registers have been re-written, which
  allows it to remove virtual register COPY LiveIntervals that become dead
  through the forwarding of all of their uses.

llvm-svn: 314729
2017-10-02 22:01:37 +00:00
Sam McCall f71bb198ed Revert "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""
This crashes on boringSSL on PPC (will send reduced testcase)

This reverts commit r312328.

llvm-svn: 312490
2017-09-04 15:47:00 +00:00
Geoff Berry 65528f2991 Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues addressed since original review:
- Moved removal of dead instructions found by
  LiveIntervals::shrinkToUses() outside of loop iterating over
  instructions to avoid instructions being deleted while pointed to by
  iterator.
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
  doing so can break code that implicitly relies on the physical
  register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
  can break the machine verifier by creating LiveRanges that don't
  end on a use (since the undef operand is not considered a use).

  [MachineCopyPropagation] Extend pass to do COPY source forwarding

  This change extends MachineCopyPropagation to do COPY source forwarding.

  This change also extends the MachineCopyPropagation pass to be able to
  be run during register allocation, after physical registers have been
  assigned, but before the virtual registers have been re-written, which
  allows it to remove virtual register COPY LiveIntervals that become dead
  through the forwarding of all of their uses.

llvm-svn: 312328
2017-09-01 14:27:20 +00:00
Hans Wennborg 24775a0a6c Revert r312154 "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""
It caused PR34387: Assertion failed: (RegNo < NumRegs && "Attempting to access record for invalid register number!")

> Issues identified by buildbots addressed since original review:
> - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
> - The pass no longer forwards COPYs to physical register uses, since
>   doing so can break code that implicitly relies on the physical
>   register number of the use.
> - The pass no longer forwards COPYs to undef uses, since doing so
>   can break the machine verifier by creating LiveRanges that don't
>   end on a use (since the undef operand is not considered a use).
>
>   [MachineCopyPropagation] Extend pass to do COPY source forwarding
>
>   This change extends MachineCopyPropagation to do COPY source forwarding.
>
>   This change also extends the MachineCopyPropagation pass to be able to
>   be run during register allocation, after physical registers have been
>   assigned, but before the virtual registers have been re-written, which
>   allows it to remove virtual register COPY LiveIntervals that become dead
>   through the forwarding of all of their uses.

llvm-svn: 312178
2017-08-30 22:11:37 +00:00
Geoff Berry feffb0c8af Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues identified by buildbots addressed since original review:
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
  doing so can break code that implicitly relies on the physical
  register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
  can break the machine verifier by creating LiveRanges that don't
  end on a use (since the undef operand is not considered a use).

  [MachineCopyPropagation] Extend pass to do COPY source forwarding

  This change extends MachineCopyPropagation to do COPY source forwarding.

  This change also extends the MachineCopyPropagation pass to be able to
  be run during register allocation, after physical registers have been
  assigned, but before the virtual registers have been re-written, which
  allows it to remove virtual register COPY LiveIntervals that become dead
  through the forwarding of all of their uses.

llvm-svn: 312154
2017-08-30 18:41:07 +00:00
Eugene Zelenko 900b633560 [CodeGen] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 312053
2017-08-29 22:32:07 +00:00
Geoff Berry bd47e8a4f7 Revert "[MachineCopyPropagation] Extend pass to do COPY source forwarding" round 2
This reverts commit r311135.

sanitizer-x86_64-linux-android buildbot is timing out with just this
patch applied.

llvm-svn: 311142
2017-08-18 01:43:11 +00:00
Geoff Berry 51f52c4fca Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Two issues identified by buildbots were addressed:
    - The pass no longer forwards COPYs to physical register uses, since
      doing so can break code that implicitly relies on the physical
      register number of the use.
    - The pass no longer forwards COPYs to undef uses, since doing so
      can break the machine verifier by creating LiveRanges that don't
      end on a use (since the undef operand is not considered a use).

    [MachineCopyPropagation] Extend pass to do COPY source forwarding

    This change extends MachineCopyPropagation to do COPY source forwarding.

    This change also extends the MachineCopyPropagation pass to be able to
    be run during register allocation, after physical registers have been
    assigned, but before the virtual registers have been re-written, which
    allows it to remove virtual register COPY LiveIntervals that become dead
    through the forwarding of all of their uses.

    Reviewers: qcolombet, javed.absar, MatzeB, jonpa

    Subscribers: jyknight, nemanjai, llvm-commits, nhaehnle, mcrosier, mgorny

    Differential Revision: https://reviews.llvm.org/D30751

llvm-svn: 311135
2017-08-17 23:06:55 +00:00
Geoff Berry 4e38e02e6f Revert "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
This reverts commit r311038.

Several buildbots are breaking, and at least one appears to be due to
the forwarding of physical regs enabled by this change.  Reverting while
I investigate further.

llvm-svn: 311062
2017-08-17 04:04:11 +00:00
Geoff Berry 87f8d25150 [MachineCopyPropagation] Extend pass to do COPY source forwarding
This change extends MachineCopyPropagation to do COPY source forwarding.

This change also extends the MachineCopyPropagation pass to be able to
be run during register allocation, after physical registers have been
assigned, but before the virtual registers have been re-written, which
allows it to remove virtual register COPY LiveIntervals that become dead
through the forwarding of all of their uses.

Reviewers: qcolombet, javed.absar, MatzeB, jonpa

Subscribers: jyknight, nemanjai, llvm-commits, nhaehnle, mcrosier, mgorny

Differential Revision: https://reviews.llvm.org/D30751

llvm-svn: 311038
2017-08-16 20:50:01 +00:00
Chandler Carruth 6bda14b313 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787
2017-06-06 11:49:48 +00:00
Matthias Braun 1527baab0c CodeGen: Rename DEBUG_TYPE to match passnames
Rename the DEBUG_TYPE to match the names of corresponding passes where
it makes sense. Also establish the pattern of simply referencing
DEBUG_TYPE instead of repeating the passname where possible.

llvm-svn: 303921
2017-05-25 21:26:32 +00:00
Matthias Braun 82e7f4d877 MachineCopyPropagation: Respect implicit operands of COPY
The code missed to check implicit operands of COPY instructions for
defs/uses.

Differential Revision: https://reviews.llvm.org/D29522

llvm-svn: 294088
2017-02-04 02:27:20 +00:00
Matthias Braun 776a1d7ecb MachineCopyPropagation: Do not consider undef operands as clobbers
This was originally introduced in r278321 to work around correctness
problems in the ExecutionDepsFix pass; Probably also to keep the
performance benefits of breaking the false dependencies which of course
also affect undef operands.

ExecutionDepsFix has been improved here recently (see for example
r278321) so we should not need this exception any longer.

Differential Revision: https://reviews.llvm.org/D29525

llvm-svn: 294087
2017-02-04 02:27:13 +00:00
Matthias Braun 1eb473680a MachineFunctionProperties/MIRParser: Rename AllVRegsAllocated->NoVRegs, compute it
Rename AllVRegsAllocated to NoVRegs. This avoids the connotation of
running after register and simply describes that no vregs are used in
a machine function. With that we can simply compute the property and do
not need to dump/parse it in .mir files.

Differential Revision: http://reviews.llvm.org/D23850

llvm-svn: 279698
2016-08-25 01:27:13 +00:00
David Majnemer 0d955d0bf5 Use the range variant of find instead of unpacking begin/end
If the result of the find is only used to compare against end(), just
use is_contained instead.

No functionality change is intended.

llvm-svn: 278433
2016-08-11 22:21:41 +00:00
Matt Arsenault 8f4d43a41f Make MachineCopyPropagation preserve CFG
This doesn't touch it as far as I can tell.

llvm-svn: 271445
2016-06-02 00:04:26 +00:00
Andrew Kaylor aa641a5171 Re-commit optimization bisect support (r267022) without new pass manager support.
The original commit was reverted because of a buildbot problem with LazyCallGraph::SCC handling (not related to the OptBisect handling).

Differential Revision: http://reviews.llvm.org/D19172

llvm-svn: 267231
2016-04-22 22:06:11 +00:00
Vedant Kumar 6013f45f92 Revert "Initial implementation of optimization bisect support."
This reverts commit r267022, due to an ASan failure:

  http://lab.llvm.org:8080/green/job/clang-stage2-cmake-RgSan_check/1549

llvm-svn: 267115
2016-04-22 06:51:37 +00:00
Andrew Kaylor f0f279291c Initial implementation of optimization bisect support.
This patch implements a optimization bisect feature, which will allow optimizations to be selectively disabled at compile time in order to track down test failures that are caused by incorrect optimizations.

The bisection is enabled using a new command line option (-opt-bisect-limit).  Individual passes that may be skipped call the OptBisect object (via an LLVMContext) to see if they should be skipped based on the bisect limit.  A finer level of control (disabling individual transformations) can be managed through an addition OptBisect method, but this is not yet used.

The skip checking in this implementation is based on (and replaces) the skipOptnoneFunction check.  Where that check was being called, a new call has been inserted in its place which checks the bisect limit and the optnone attribute.  A new function call has been added for module and SCC passes that behaves in a similar way.

Differential Revision: http://reviews.llvm.org/D19172

llvm-svn: 267022
2016-04-21 17:58:54 +00:00
Derek Schuff ad154c837e Introduce MachineFunctionProperties and the AllVRegsAllocated property
MachineFunctionProperties represents a set of properties that a MachineFunction
can have at particular points in time. Existing examples of this idea are
MachineRegisterInfo::isSSA() and MachineRegisterInfo::tracksLiveness() which
will eventually be switched to use this mechanism.
This change introduces the AllVRegsAllocated property; i.e. the property that
all virtual registers have been allocated and there are no VReg operands
left.

With this mechanism, passes can declare that they require a particular property
to be set, or that they set or clear properties by implementing e.g.
MachineFunctionPass::getRequiredProperties(). The MachineFunctionPass base class
verifies that the requirements are met, and handles the setting and clearing
based on the delcarations. Passes can also directly query and update the current
properties of the MF if they want to have conditional behavior.

This change annotates the target-independent post-regalloc passes; future
changes will also annotate target-specific ones.

Reviewers: qcolombet, hfinkel

Differential Revision: http://reviews.llvm.org/D18421

llvm-svn: 264593
2016-03-28 17:05:30 +00:00
Jun Bum Lim 36c53fe147 [MachineCopyPropagation] Expose more dead copies across instructions with regmasks
When encountering instructions with regmasks, instead of cleaning up all the
elements in MaybeDeadCopies map, remove only the instructions erased. By keeping
more instruction in MaybeDeadCopies, this change will expose more dead copies
across instructions with regmasks.

llvm-svn: 264462
2016-03-25 21:15:35 +00:00
Matthias Braun 9dcd65f478 MachineCopyPropagation: Catch copies of the form A<-B;A<-B
Differential Revision: http://reviews.llvm.org/D17475

llvm-svn: 261966
2016-02-26 03:18:55 +00:00
Matthias Braun e39ff70685 MachineCopyPropagation: Keep scanning through instructions with regmasks
This also simplifies the code by removing the overly conservative
NoInterveningSideEffect() function. This function checked:
- That the two copies belong to the same block: We only process one
  block at a time and clear our maps in between it is impossible to find a
  copy from a different block.
- There is no terminator between the two copy instructions: This is not
  allowed anyway (the MachineVerifier would complain)
- Does not have instructions with hasUnmodeledSideEffects() or isCall()
  set: Even for those instructuction we must have all clobbers/defs of
  registers explicit as an operand. If the register is explicitely
  clobbered we would never come to the point of checking for
  NoInterveningSideEffect() anyway.

(I also checked this with a temporary build of the test-suite with all
 potentially failing conditions in NoInterveningSideEffect() turned into
 asserts)

Differential Revision: http://reviews.llvm.org/D17474

llvm-svn: 261965
2016-02-26 03:18:50 +00:00
Duncan P. N. Exon Smith c5b668deb8 Revert "CodeGen: MachineInstr::getIterator() => getInstrIterator(), NFC"
This reverts commit r261504, since it's not obvious the new name is
better:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160222/334298.html

I'll recommit if we get consensus that it's the right direction.

llvm-svn: 261567
2016-02-22 20:49:58 +00:00
Duncan P. N. Exon Smith dc0848c029 CodeGen: MachineInstr::getIterator() => getInstrIterator(), NFC
Delete MachineInstr::getIterator(), since the term "iterator" is
overloaded when talking about MachineInstr.

- Downcast to ilist_node in iplist::getNextNode() and getPrevNode() so
  that ilist_node::getIterator() is still available.
- Add it back as MachineInstr::getInstrIterator().  This matches the
  naming in MachineBasicBlock.
- Add MachineInstr::getBundleIterator().  This is explicitly called
  "bundle" (not matching MachineBasicBlock) to disintinguish it clearly
  from ilist_node::getIterator().
- Update all calls.  Some of these I switched to `auto` to remove
  boiler-plate, since the new name is clear about the type.

There was one call I updated that looked fishy, but it wasn't clear what
the right answer was.  This was in X86FrameLowering::inlineStackProbe(),
added in r252578 in lib/Target/X86/X86FrameLowering.cpp.  I opted to
leave the behaviour unchanged, but I'll reply to the original commit on
the list in a moment.

llvm-svn: 261504
2016-02-21 22:58:35 +00:00
Matthias Braun c65e904be8 MachineCopyPropagation: Introduce Reg2MIMap typedef; NFC
llvm-svn: 261408
2016-02-20 03:56:41 +00:00
Matthias Braun bd18d751de MachineCopyPropagation: Move variables from function to pass
This avoids unnecessarily passing them around when calling helper
functions. It may also be slightly faster to call clear() on the
datastructures instead of freshly initializing them for each block.

llvm-svn: 261407
2016-02-20 03:56:39 +00:00
Matthias Braun 273575dcbe MachineCopyPropagation: Use ranged for, cleanup; NFC
llvm-svn: 261406
2016-02-20 03:56:36 +00:00
Matthias Braun 57b5f11aa7 MachineCopyPropagation: Use assert() instead of if{report_error()} for 'impossible' condition
llvm-svn: 261405
2016-02-20 03:56:33 +00:00
Jun Bum Lim 59df5e89c2 [MachineCopyPropagation] Fix comment. NFC
Reviewers: MatzeB, qcolombet, jmolloy, mcrosier

Subscribers: llvm-commits, mcrosier

Differential Revision: http://reviews.llvm.org/D16806

llvm-svn: 259656
2016-02-03 15:56:27 +00:00
Alexander Kornienko f00654e31b Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Alexander Kornienko 70bc5f1398 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Matthias Braun 165d467125 MachineCopyPropagation: Remove the copies instead of using KILL instructions.
For some history here see the commit messages of r199797 and r169060.

The original intent was to fix cases like:

%EAX<def> = COPY %ECX<kill>, %RAX<imp-def>
%RCX<def> = COPY %RAX<kill>

where simply removing the copies would have RCX undefined as in terms of
machine operands only the ECX part of it is defined. The machine
verifier would complain about this so 169060 changed such COPY
instructions into KILL instructions so some super-register imp-defs
would be preserved. In r199797 it was finally decided to always do this
regardless of super-register defs.

But this is wrong, consider:
R1 = COPY R0
...
R0 = COPY R1
getting changed to:
R1 = KILL R0
...
R0 = KILL R1

It now looks like R0 dies at the first KILL and won't be alive until the
second KILL, while in reality R0 is alive and must not change in this
part of the program.

As this only happens after register allocation there is not much code
still performing liveness queries so the issue was not noticed.  In fact
I didn't manage to create a testcase for this, without unrelated changes
I am working on at the moment.

The fix is simple: As of r223896 the MachineVerifier allows reads from
partially defined registers, so the whole transforming COPY->KILL thing
is not necessary anymore. This patch also changes a similar (but more
benign case as the def and src are the same register) case in the
VirtRegRewriter.

Differential Revision: http://reviews.llvm.org/D10117

llvm-svn: 238588
2015-05-29 18:19:25 +00:00
Quentin Colombet 75afbfd4a1 [MachineCopyPropagation] Fix a bug with undef handling when the value is actualy alive.
Test case will follow.

llvm-svn: 238518
2015-05-28 22:38:40 +00:00
Quentin Colombet 796d906e06 [MachineCopyPropagation] Handle undef flags conservatively so that we do not
remove copies that are useful after breaking some hardware dependencies.
In other words, handle this kind of situations conservatively by assuming reg2
is redefined by the undef flag.
reg1 = copy reg2
= inst reg2<undef>
reg2 = copy reg1
Copy propagation used to remove the last copy.
This is incorrect because the undef flag on reg2 in inst, allows next
passes to put whatever trashed value in reg2 that may help.
In practice we end up with this code:
reg1 = copy reg2
reg2 = 0
= inst reg2<undef>
reg2 = copy reg1

This fixes PR21743.

llvm-svn: 235647
2015-04-23 21:17:39 +00:00
Hao Liu 04183242b3 [MachineCopyPropagation] Fix a bug causing incorrect removal for the instruction sequences as follows
%Q5_Q6<def> = COPY %Q2_Q3
   %D5<def> =
   %D3<def> =
   %D3<def> = COPY %D6     // Incorrectly removed in MachineCopyPropagation
   Using of %D3 results in incorrect result ...

   Reviewed in http://reviews.llvm.org/D8242 

llvm-svn: 232142
2015-03-13 05:15:23 +00:00