Commit Graph

48 Commits

Author SHA1 Message Date
Craig Topper c3c20c83f3 [X86] Fix typo in comment. NFC 2020-02-15 12:48:19 -08:00
Hiroshi Yamauchi d9ae493937 [PGO][PGSO] Instrument the code gen / target passes.
Summary:
Split off of D67120.

Add the profile guided size optimization instrumentation / queries in the code
gen or target passes. This doesn't enable the size optimizations in those passes
yet as they are currently disabled in shouldOptimizeForSize (for non-IR pass
queries).

A second try after reverted D71072.

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71149
2019-12-09 12:42:59 -08:00
Hiroshi Yamauchi 2eb30fafa5 Revert "[PGO][PGSO] Instrument the code gen / target passes."
This reverts commit 9a0b5e1407.

This seems to break buildbots.
2019-12-06 12:17:32 -08:00
Hiroshi Yamauchi 9a0b5e1407 [PGO][PGSO] Instrument the code gen / target passes.
Summary:
Split off of D67120.

Add the profile guided size optimization instrumentation / queries in the code
gen or target passes. This doesn't enable the size optimizations in those passes
yet as they are currently disabled in shouldOptimizeForSize (for non-IR pass
queries).

Reviewers: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71072
2019-12-06 10:43:39 -08:00
Simon Pilgrim eabd405e66 [X86] Fix uninitialized variable warnings. NFCI. 2019-11-06 14:02:43 +00:00
Craig Topper 0364d89b6d [X86] Teach FixupBWInsts to turn MOVSX16rr8/MOVZX16rr8/MOVSX16rm8/MOVZX16rm8 into their 32-bit dest equivalents when the upper part of the register is dead.
llvm-svn: 371240
2019-09-06 19:14:49 +00:00
Craig Topper 7739fbc9c3 [X86] Fix bad indentation. NFC
llvm-svn: 371167
2019-09-06 05:50:46 +00:00
Craig Topper a17d1d2250 [X86] Use Register/MCRegister in more places in X86
This was a quick pass through some obvious places. I haven't tried the clang-tidy check.

I also replaced the zeroes in getX86SubSuperRegister with X86::NoRegister which is the real sentinel name.

Differential Revision: https://reviews.llvm.org/D66363

llvm-svn: 369151
2019-08-16 20:50:23 +00:00
Daniel Sanders 0c47611131 Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVM
Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).

Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor

Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&

Depends on D65919

Reviewers: arsenm, bogner, craig.topper, RKSimon

Reviewed By: arsenm

Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65962

llvm-svn: 369041
2019-08-15 19:22:08 +00:00
Tom Stellard f335672218 X86: Clean up pass initialization
Summary:
- Remove redundant initializations from pass constructors that were
  already being initialized by LLVMInitializeX86Target().

- Add initialization function for the FPS pass.

Reviewers: craig.topper

Reviewed By: craig.topper

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63218

llvm-svn: 363221
2019-06-13 02:09:32 +00:00
Evandro Menezes 85bd3978ae [IR] Refactor attribute methods in Function class (NFC)
Rename the functions that query the optimization kind attributes.

Differential revision: https://reviews.llvm.org/D60287

llvm-svn: 357731
2019-04-04 22:40:06 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Chandler Carruth c73c0307fe [MI] Change the array of `MachineMemOperand` pointers to be
a generically extensible collection of extra info attached to
a `MachineInstr`.

The primary change here is cleaning up the APIs used for setting and
manipulating the `MachineMemOperand` pointer arrays so chat we can
change how they are allocated.

Then we introduce an extra info object that using the trailing object
pattern to attach some number of MMOs but also other extra info. The
design of this is specifically so that this extra info has a fixed
necessary cost (the header tracking what extra info is included) and
everything else can be tail allocated. This pattern works especially
well with a `BumpPtrAllocator` which we use here.

I've also added the basic scaffolding for putting interesting pointers
into this, namely pre- and post-instruction symbols. These aren't used
anywhere yet, they're just there to ensure I've actually gotten the data
structure types correct. I'll flesh out support for these in
a subsequent patch (MIR dumping, parsing, the works).

Finally, I've included an optimization where we store any single pointer
inline in the `MachineInstr` to avoid the allocation overhead. This is
expected to be the overwhelmingly most common case and so should avoid
any memory usage growth due to slightly less clever / dense allocation
when dealing with >1 MMO. This did require several ergonomic
improvements to the `PointerSumType` to reasonably support the various
usage models.

This also has a side effect of freeing up 8 bits within the
`MachineInstr` which could be repurposed for something else.

The suggested direction here came largely from Hal Finkel. I hope it was
worth it. ;] It does hopefully clear a path for subsequent extensions
w/o nearly as much leg work. Lots of thanks to Reid and Justin for
careful reviews and ideas about how to do all of this.

Differential Revision: https://reviews.llvm.org/D50701

llvm-svn: 339940
2018-08-16 21:30:05 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Andrei Elovikov c560a18c7f [X86FixupBWInsts] Fix miscompilation if sibling sub-register is live.
Summary: The issues was found during D40524.

Reviewers: andrew.w.kaylor, craig.topper, MatzeB

Reviewed By: andrew.w.kaylor

Subscribers: aivchenk, llvm-commits

Differential Revision: https://reviews.llvm.org/D42533

llvm-svn: 323635
2018-01-29 09:26:04 +00:00
Andrew Kaylor e12e08c680 Handle the case of live 16-bit subregisters in X86FixupBWInsts
Differential Revision: https://reviews.llvm.org/D40524

Change-Id: Ie3a405b28503ceae999f5f3ba07a68fa733a2400
llvm-svn: 321674
2018-01-02 21:04:38 +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
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 25528d6de7 [CodeGen] Unify MBB reference format in both MIR and debug output
As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.

The MIR printer prints the IR name of a MBB only for block definitions.

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix

Differential Revision: https://reviews.llvm.org/D40422

llvm-svn: 319665
2017-12-04 17:18:51 +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 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
Nikolai Bozhenov 84af99b3b1 [X86FixupBWInsts] More precise register liveness if no <imp-use> on MOVs.
Summary:
Subregister liveness tracking is not implemented for X86 backend, so
sometimes the whole super register is said to be live, when only a
subregister is really live. That might happen if the def and the use
are located in different MBBs, see added fixup-bw-isnt.mir test.

However, using knowledge of the specific instructions handled by the
bw-fixup-pass we can get more precise liveness information which this
change does.

Reviewers: MatzeB, DavidKreitzer, ab, andrew.w.kaylor, craig.topper

Reviewed By: craig.topper

Subscribers: n.bozhenov, myatsina, llvm-commits, hiraditya

Patch by Andrei Elovikov <andrei.elovikov@intel.com>

Differential Revision: https://reviews.llvm.org/D37559

llvm-svn: 313524
2017-09-18 10:17:59 +00:00
Hiroshi Inoue 7f46baff2c fix typos in comments; NFC
llvm-svn: 308127
2017-07-16 08:11:56 +00:00
Zvi Rackover db4b032205 X86FixupBWInsts: Minor cleanup. NFC
Summary: Cleanup some remnants of code from when the X86FixupBWInsts pass did both forward liveness analysis and backward liveness analysis.

Reviewers: MatzeB, myatsina, DavidKreitzer

Reviewed By: MatzeB

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31264

llvm-svn: 298599
2017-03-23 14:08:26 +00:00
Diana Picus 116bbab4e4 [CodeGen] Rename MachineInstrBuilder::addOperand. NFC
Rename from addOperand to just add, to match the other method that has been
added to MachineInstrBuilder for adding more than just 1 operand.

See https://reviews.llvm.org/D28057 for the whole discussion.

Differential Revision: https://reviews.llvm.org/D28556

llvm-svn: 291891
2017-01-13 09:58:52 +00:00
Matthias Braun 0c989a893b LivePhysReg: Use reference instead of pointer in init(); NFC
llvm-svn: 289002
2016-12-08 00:15:51 +00:00
Mehdi Amini 117296c0a0 Use StringRef in Pass/PassManager APIs (NFC)
llvm-svn: 283004
2016-10-01 02:56:57 +00:00
Craig Topper ed71f04abb [X86] Remove stale comment about FixupBWInsts pass being off by default. NFC
llvm-svn: 279915
2016-08-27 05:26:54 +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
Matthias Braun 96ec47db74 X86FixupBWInsts: No need for forward liveness analysis.
With r274952 and r275201 in place there are no cases left where a
forward liveness analysis yields different results than a backward one.
So we can remove the forward stepping logic.

Differential Revision: http://reviews.llvm.org/D22083

llvm-svn: 275204
2016-07-12 19:04:30 +00:00
Kevin B. Smith 4f81990049 [X86]: Fix for uninitialized access introduced in r272797.
llvm-svn: 272835
2016-06-15 20:52:19 +00:00
Kevin B. Smith c3c82cdbd0 [X86]: Improve Liveness checking for X86FixupBWInsts.cpp
Differential Revision: http://reviews.llvm.org/D21085

llvm-svn: 272797
2016-06-15 16:03:06 +00:00
Ahmed Bougacha 04a8fc2e37 [X86] Teach X86FixupBWInsts to promote MOV8rr/MOV16rr to MOV32rr.
This re-applies r268760, reverted in r268794.
Fixes http://llvm.org/PR27670

The original imp-defs assertion was way overzealous: forward all
implicit operands, except imp-defs of the new super-reg def (r268787
for GR64, but also possible for GR16->GR32), or imp-uses of the new
super-reg use.
While there, mark the source use as Undef, and add an imp-use of the
old source reg: that should cover any case of dead super-regs.

At the stage the pass runs, flags are unlikely to matter anyway;
still, let's be as correct as possible.

Also add MIR tests for the various interesting cases.

Original commit message:
Codesize is less (16) or equal (8), and we avoid partial
dependencies.

Differential Revision: http://reviews.llvm.org/D19999

llvm-svn: 268831
2016-05-07 01:11:17 +00:00
Ahmed Bougacha 068ac4af39 [X86] Register and initialize the FixupBW pass.
That lets us use it in MIR tests.

llvm-svn: 268830
2016-05-07 01:11:10 +00:00
Nico Weber 9b32b4fbee Revert r268760, it caused PR27670.
llvm-svn: 268794
2016-05-06 21:07:02 +00:00
Ahmed Bougacha 505984b466 [X86] Accept imp-defs of GR64 super-registers in FixupBW MOVrr.
Testcase will follow shortly.

llvm-svn: 268787
2016-05-06 20:03:03 +00:00
Ahmed Bougacha 258426ca7a [X86] Teach X86FixupBWInsts to promote MOV8rr/MOV16rr to MOV32rr.
Codesize is less (16) or equal (8), and we avoid partial dependencies.

Differential Revision: http://reviews.llvm.org/D19999

llvm-svn: 268760
2016-05-06 17:42:57 +00:00
Ahmed Bougacha 04200a7c86 [X86] Remove \brief in FixupBW. NFC.
llvm-svn: 268754
2016-05-06 17:28:47 +00:00
Ahmed Bougacha cfd9e55e90 [X86] Simplify FixupBW sub_8bit_hi-related logic. NFC.
Instead of passing around sizes and asking for subregs, we can check
the subreg indices we care about: sub_8bit_hi and sub_8bit.

Differential Revision: http://reviews.llvm.org/D20006

llvm-svn: 268753
2016-05-06 17:28:42 +00:00
Matthias Braun d1aabb2813 livePhysRegs: Pass MBB by reference in addLive{Ins|Outs}(); NFC
The block must no be nullptr for the addLiveIns()/addLiveOuts()
function.

llvm-svn: 268340
2016-05-03 00:24:32 +00:00
Matthias Braun 24f26e6d91 LivePhysRegs: Automatically determine presence of pristine regs.
Remove the AddPristinesAndCSRs parameters from
addLiveIns()/addLiveOuts().

We need to respect pristine registers after prologue epilogue insertion,
Seeing that we got this wrong in at least two commits already, we should
rather pay the small price to query MachineFrameInfo for it.

There are three cases that did not set AddPristineAndCSRs to true even
after register allocation:
- ExecutionDepsFix: live-out registers are used as a hint that the
  register is used soon. This is not true for pristine registers so
  use the new addLiveOutsNoPristines() to maintain this behaviour.
- SystemZShortenInst: Not setting AddPristineAndCSRs to true looks like
  a bug, should do the right thing automatically now.
- StackMapLivenessAnalysis: Not adding pristine registers looks like a
  bug to me. Added a FIXME comment but maintain the current behaviour
  as a change may need to get coordinated with GC runtimes.

llvm-svn: 268336
2016-05-03 00:08:46 +00:00
Ahmed Bougacha 9a0c9adade [X86] Set AddPristinesAndCSRs to FixupBW LivePhysRegs. NFC.
We run after PEI, so we need to AddPristinesAndCSRs.
In practice, that makes no difference here, because we only ask about
liveness of super-registers of defined GR8/GR16 registers, so they
can't be pristine. Still, it's the correct thing to do.

Thanks to Quentin for noticing!

Follow-up to r267495.

llvm-svn: 267658
2016-04-27 01:51:38 +00:00
Andrew Kaylor 2bee5ef462 Optimization bisect support in X86-specific passes
Differential Revision: http://reviews.llvm.org/D19439

llvm-svn: 267608
2016-04-26 21:44:24 +00:00
Ahmed Bougacha 5cf735a5b1 [X86] Use LivePhysRegs in X86FixupBWInsts.
Kill-flags, which computeRegisterLiveness uses, are not reliable.
LivePhysRegs is.

Differential Revision: http://reviews.llvm.org/D19472

llvm-svn: 267495
2016-04-26 00:00:48 +00:00
Kevin B. Smith e0a6fc3bcc [X86] Fix PR23155 by turning on X86FixupBWInsts by default.
Differential Revision: http://reviews.llvm.org/D18866

llvm-svn: 265830
2016-04-08 18:58:29 +00:00
Derek Schuff 1dbf7a571f Add MachineFunctionProperty checks for AllVRegsAllocated for target passes
Summary:
This adds the same checks that were added in r264593 to all
target-specific passes that run after register allocation.

Reviewers: qcolombet

Subscribers: jyknight, dsanders, llvm-commits

Differential Revision: http://reviews.llvm.org/D18525

llvm-svn: 265313
2016-04-04 17:09:25 +00:00
Kevin B. Smith 6a83350bee [X86] New pass to change byte and word instructions to zero-extending versions.
Differential Revision: http://reviews.llvm.org/D17032

llvm-svn: 260572
2016-02-11 19:43:04 +00:00