Commit Graph

3643 Commits

Author SHA1 Message Date
Simon Dardis b432a3ed7e [mips] Tighten FastISel restrictions
LLVM PR/29052 highlighted that FastISel for MIPS attempted to lower
arguments assuming that it was using the paired 32bit registers to
perform operations for f64. This mode of operation is not supported
for MIPSR6.

This patch resolves the reported issue by adding additional checks
for unsupported floating point unit configuration.

Thanks to mike.k for reporting this issue!

Reviewers: seanbruno, vkalintiris

Differential Review: https://reviews.llvm.org/D23795

llvm-svn: 280706
2016-09-06 12:36:24 +00:00
Simon Dardis 1fa1fb0f8d [mips] Include missed file from previous commit
llvm-svn: 280377
2016-09-01 15:03:13 +00:00
Simon Dardis bd27154757 [mips] interAptiv based generic schedule model
This scheduler describes a processor which covers all MIPS ISAs based
around the interAptiv and P5600 timings.

Reviewers: vkalintiris, dsanders

Differential Revision: https://reviews.llvm.org/D23551

llvm-svn: 280374
2016-09-01 14:53:53 +00:00
Hal Finkel 5081ac27c7 Add ISD::EH_DWARF_CFA, simplify @llvm.eh.dwarf.cfa on Mips, fix on PowerPC
LLVM has an @llvm.eh.dwarf.cfa intrinsic, used to lower the GCC-compatible
__builtin_dwarf_cfa() builtin. As pointed out in PR26761, this is currently
broken on PowerPC (and likely on ARM as well). Currently, @llvm.eh.dwarf.cfa is
lowered using:

  ADD(FRAMEADDR, FRAME_TO_ARGS_OFFSET)

where FRAME_TO_ARGS_OFFSET defaults to the constant zero. On x86,
FRAME_TO_ARGS_OFFSET is lowered to 2*SlotSize. This setup, however, does not
work for PowerPC. Because of the way that the stack layout works, the canonical
frame address is not exactly (FRAMEADDR + FRAME_TO_ARGS_OFFSET) on PowerPC
(there is a lower save-area offset as well), so it is not just a matter of
implementing FRAME_TO_ARGS_OFFSET for PowerPC (unless we redefine its
semantics -- We can do that, since it is currently used only for
@llvm.eh.dwarf.cfa lowering, but the better to directly lower the CFA construct
itself (since it can be easily represented as a fixed-offset FrameIndex)). Mips
currently does this, but by using a custom lowering for ADD that specifically
recognizes the (FRAMEADDR, FRAME_TO_ARGS_OFFSET) pattern.

This change introduces a ISD::EH_DWARF_CFA node, which by default expands using
the existing logic, but can be directly lowered by the target. Mips is updated
to use this method (which simplifies its implementation, and I suspect makes it
more robust), and updates PowerPC to do the same.

Fixes PR26761.

Differential Revision: https://reviews.llvm.org/D24038

llvm-svn: 280350
2016-09-01 10:28:47 +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
Simon Dardis f114820912 [mips] Preparatory work for a generic scheduler
Extend instruction definitions from nearly all ISAs to include
appropriate instruction itineraries. Change MIPS16s gp prologue
generation to use real instructions instead of using a pseudo
instruction.

Reviewers: dsanders, vkalintiris

Differential Review: https://reviews.llvm.org/D23548

llvm-svn: 279623
2016-08-24 13:00:47 +00:00
Simon Atanasyan eb9ed61021 [mips][ias] Support .dtprel[d]word and .tprel[d]word directives
Assembler directives .dtprelword, .dtpreldword, .tprelword, and
.tpreldword generates relocations R_MIPS_TLS_DTPREL32, R_MIPS_TLS_DTPREL64,
R_MIPS_TLS_TPREL32, and R_MIPS_TLS_TPREL64 respectively.

The main motivation for this patch is to be able to write test cases
for checking correctness of the LLD linker's behaviour.

Differential Revision: https://reviews.llvm.org/D23669

llvm-svn: 279439
2016-08-22 16:18:42 +00:00
Hrvoje Varga f0ed16eae5 [mips][microMIPS] Implement BLTZC, BLEZC, BGEZC and BGTZC instructions, fix disassembly and add operand checking to existing B<cond>C implementations
Differential Revision: https://reviews.llvm.org/D22667

llvm-svn: 279429
2016-08-22 12:17:59 +00:00
Michael Kuperstein 2bc3d4d46c [SelectionDAG] Rename fextend -> fpextend, fround -> fpround, frnd -> fround
The names of the tablegen defs now match the names of the ISD nodes.
This makes the world a slightly saner place, as previously "fround" matched
ISD::FP_ROUND and not ISD::FROUND.

Differential Revision: https://reviews.llvm.org/D23597

llvm-svn: 279129
2016-08-18 20:08:15 +00:00
Simon Dardis ea3431598e [mips] Correct tail call encoding for MIPSR6
r277708 enabled tails calls for MIPS but used the 'jr' instruction when the 
jump target was held in a register. For MIPSR6, 'jalr $zero, $reg' should
have been used. Additionally, add missing patterns for external and global
symbols for tail calls.

Reviewers: dsanders, vkalintiris

Differential Review: https://reviews.llvm.org/D23301

llvm-svn: 279064
2016-08-18 13:22:43 +00:00
Justin Bogner cd1d5aaf2e Replace a few more "fall through" comments with LLVM_FALLTHROUGH
Follow up to r278902. I had missed "fall through", with a space.

llvm-svn: 278970
2016-08-17 20:30:52 +00:00
Simon Dardis ac96ec7906 [mips] Add l.[sd] and s.[sd] instruction aliases
Reviewers: dsanders, vkalintiris

Differential Review: https://reviews.llvm.org/D23121

llvm-svn: 278930
2016-08-17 14:45:09 +00:00
Justin Bogner b03fd12cef Replace "fallthrough" comments with LLVM_FALLTHROUGH
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.

llvm-svn: 278902
2016-08-17 05:10:15 +00:00
Simon Dardis 4893aff94e [mips] Enforce compact branch restrictions
Check both operands for use of the $zero register which cannot be used with
a compact branch instruction.

Reviewers: dsanders, vkalintris

Differential Review: https://reviews.llvm.org/D23547

llvm-svn: 278824
2016-08-16 17:16:11 +00:00
Duncan P. N. Exon Smith f197b1f78f ADT: Remove all ilist_iterator => pointer casts, NFC
Remove all ilist_iterator to pointer casts.  There were two reasons for
casts:

  - Checking for an uninitialized (i.e., null) iterator.  I added
    MachineInstrBundleIterator::isValid() to check for that case.

  - Comparing an iterator against the underlying pointer value while
    avoiding converting the pointer value to an iterator.  This is
    occasionally necessary in MachineInstrBundleIterator, since there is
    an assertion in the constructors that the underlying MachineInstr is
    not bundled (but we don't care about that if we're just checking for
    pointer equality).

To support the latter case, I rewrote the == and != operators for
ilist_iterator and MachineInstrBundleIterator.

  - The implicit constructors now use enable_if to exclude
    const-iterator => non-const-iterator conversions from overload
    resolution (previously it was a compiler error on instantiation, now
    it's SFINAE).

  - The == and != operators are now global (friends), and are not
    templated.

  - MachineInstrBundleIterator has overloads to compare against both
    const_pointer and const_reference.  This avoids the implicit
    conversions to MachineInstrBundleIterator that assert, instead just
    checking the address (and I added unit tests to confirm this).

Notably, the only remaining uses of ilist_iterator::getNodePtrUnchecked
are in ilist.h, and no code outside of ilist*.h directly relies on this
UB end-iterator-to-pointer conversion anymore.  It's still needed for
ilist_*sentinel_traits, but I'll clean that up soon.

llvm-svn: 278478
2016-08-12 05:05:36 +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
Daniel Sanders 3feeb9c851 Re-commit r277988: [mips][ias] Fix all the hacks related to MIPS-specific unary operators (%hi/%lo/%gp_rel/etc.).
Hopefully with the MSVC builds fixed. I've added a missing '#include <tuple>'
that gcc and clang don't seem to need.

llvm-svn: 277995
2016-08-08 11:50:25 +00:00
Daniel Sanders cae9aeed39 Revert r277988: [mips][ias] Fix all the hacks related to MIPS-specific unary operators (%hi/%lo/%gp_rel/etc.).
It seems that MSVC doesn't like std::tie().

llvm-svn: 277990
2016-08-08 09:33:14 +00:00
Daniel Sanders 2ab623b5a3 [mips][ias] Fix all the hacks related to MIPS-specific unary operators (%hi/%lo/%gp_rel/etc.).
Summary:
They are now lexed as a single token on targets where
MCAsmInfo::HasMipsExpressions is true and then parsed in a similar way to
the '~' operator as part of MCExpr::parseExpression.

As a result:
* expressions and immediates no longer have different parsing rules. The
  difference is now solely down to whether evaluateAsAbsolute() succeeds.
* %hi(%neg(%gp_rel(x))) are no longer parsed as a single operator and
  decomposed into the three MipsMCExpr nodes. They are parsed directly as
  three MipsMCExpr nodes.
  * parseMemOperand no longer needs to eat all the surrounding parenthesis
    to get at the outermost operator to make this work
* %hi(%neg(%gp_rel(x))) and %lo(%neg(%gp_rel(x))) are no longer the only
  3-in-1 relocs that parse for N64. They're still the only combinations that
  are permitted in relocatable expressions though. Fixing that should be a
  later patch.
* We no longer need to list all the tokens that can occur as the first token of
  an expression or immediate.

test/MC/Mips/expr1.s:
    This change also prevents the incorrect lowering of %lo(2*4)+foo to
    %lo(8+foo) which is not an equivalent expression (the difference is
    whether foo is truncated to 16-bit or not) and the test has been
    updated to account for the macro expansion the correct expression requires.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: https://reviews.llvm.org/D23110

llvm-svn: 277988
2016-08-08 09:20:52 +00:00
Hrvoje Varga 846bdb746d [mips][microMIPS] Implement CFC1, CFC2, CTC1 and CTC2 instructions
Differential Revision: https://reviews.llvm.org/D22347

llvm-svn: 277719
2016-08-04 11:22:52 +00:00
Simon Dardis 57f4ae4625 [mips] Enable tail calls by default
Enable tail calls by default for (micro)MIPS(64).

microMIPS is slightly more tricky than doing it for MIPS(R6) or microMIPSR6.
microMIPS has two instruction encodings: 16bit and 32bit along with some
restrictions on the size of the instruction that can fill the delay slot.
For safe tail calls for microMIPS, the delay slot filler attempts to find
a correct size instruction for the delay slot of TAILCALL pseudos.

Reviewers: dsanders, vkalintris

Subscribers: jfb, dsanders, sdardis, llvm-commits

Differential Revision: https://reviews.llvm.org/D21138

llvm-svn: 277708
2016-08-04 09:17:07 +00:00
Simon Dardis 6c3591d33e [mips] Update the P5600 scheduler for isComplete = 1
These changes update the schedule model for the P5600 and includes the
rest of the MSA and MIPS32R5 instruction sets.

Reviewers: dsanders, vkalintris

Differential Revision: https://reviews.llvm.org/D21835

llvm-svn: 277441
2016-08-02 10:32:00 +00:00
Daniel Sanders b3ae33c7a6 [mips][fastisel] Correct argument lowering for (f64, f64, i32) and similar.
Summary:
Allocating an AFGR64 shadows two GPR32's instead of just one.

This fixes an LNT regression detected by our internal buildbots.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: https://reviews.llvm.org/D23012

llvm-svn: 277348
2016-08-01 15:32:51 +00:00
Simon Pilgrim 2ddeee1784 Fixed MSVC out of range shift warning
llvm-svn: 277333
2016-08-01 09:40:38 +00:00
Hrvoje Varga 00d96ee7b9 [mips] Clang generates unaligned offset for MSA instruction st.d
Differential Revision: https://reviews.llvm.org/D19475

llvm-svn: 277323
2016-08-01 06:46:20 +00:00
Daniel Sanders cbaca42a03 Re-commit: [mips][fastisel] Handle 0-4 arguments without SelectionDAG.
Summary:
Implements fastLowerArguments() to avoid the need to fall back on
SelectionDAG for 0-4 argument functions that don't do tricky things like
passing double in a pair of i32's.

This allows us to move all except one test to -fast-isel-abort=3. The
remaining one has function prototypes of the form 'i32 (i32, double, double)'
which requires floats to be passed in GPR's.

The previous commit had an uninitialized variable that caused the incoming
argument region to have undefined size. This has been fixed.

Reviewers: sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: https://reviews.llvm.org/D22680

llvm-svn: 277136
2016-07-29 12:27:28 +00:00
Sjoerd Meijer 0eb96ed0de TargetInstrInfo: add virtual function getInstSizeInBytes
This adds a target hook getInstSizeInBytes to TargetInstrInfo that a lot of
subclasses already implement.

Differential Revision: https://reviews.llvm.org/D22885

llvm-svn: 277126
2016-07-29 08:16:16 +00:00
Matthias Braun 941a705b7b MachineFunction: Return reference for getFrameInfo(); NFC
getFrameInfo() never returns nullptr so we should use a reference
instead of a pointer.

llvm-svn: 277017
2016-07-28 18:40:00 +00:00
Sjoerd Meijer 89217f8835 TargetInstrInfo: rename GetInstSizeInBytes to getInstSizeInBytes. NFC
Differential Revision: https://reviews.llvm.org/D22925

llvm-svn: 276997
2016-07-28 16:32:22 +00:00
Daniel Sanders b23005ead4 [mips] Fix a warning that occurs on some gcc 4.9.2's but not all of them.
llvm-svn: 276993
2016-07-28 15:59:06 +00:00
Daniel Sanders 6e74651658 Revert r276982 and r276984: [mips][fastisel] Handle 0-4 arguments without SelectionDAG
It seems that the stack offset in callabi.ll varies between machines. I'll look
into it.

llvm-svn: 276989
2016-07-28 15:37:42 +00:00
Daniel Sanders 313755d9ef [mips] Reword debug message as should have been done before committing r276982
llvm-svn: 276984
2016-07-28 15:13:23 +00:00
Daniel Sanders e0b529f619 [mips][fastisel] Handle 0-4 arguments without SelectionDAG.
Summary:
Implements fastLowerArguments() to avoid the need to fall back on
SelectionDAG for 0-4 argument functions that don't do tricky things like
passing double in a pair of i32's.

This allows us to move all except one test to -fast-isel-abort=3. The
remaining one has function prototypes of the form 'i32 (i32, double, double)'
which requires floats to be passed in GPR's.

Reviewers: sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: https://reviews.llvm.org/D22680

llvm-svn: 276982
2016-07-28 14:55:28 +00:00
Daniel Sanders c5537427c2 [mips][ias] Check '$rs = $rd' constraints when both registers are in AsmText.
Summary:
This is one possible solution to the problem of ignoring constraints that Simon
raised in D21473 but it's a bit of a hack.

The integrated assembler currently ignores violations of the tied register
constraints when the operands involved in a tie are both present in the AsmText.
For example, 'dati $rs, $rt, $imm' with the '$rs = $rt' will silently replace
$rt with $rs. So 'dati $2, $3, 1' is processed as if the user provided
'dati $2, $2, 1' without any diagnostic being emitted.

This is difficult to solve properly because there are multiple parts of the
matcher that are silently forcing these constraints to be met. Tied operands are
rendered to instructions by cloning previously rendered operands but this is
unnecessary because the matcher was already instructed to render the operand it
would have cloned. This is also unnecessary because earlier code has already
replaced the MCParsedOperand with the one it was tied to (so the parsed input
is matched as if it were 'dati <RegIdx 2>, <RegIdx 2>, <Imm 1>'). As a result,
it looks like fixing this properly amounts to a rewrite of the tied operand
handling which affects all targets.

This patch however, merely inserts a checking hook just before the
substitution of MCParsedOperands and the Mips target overrides it. It's not
possible to accurately check the registers are the same this early (because
numeric registers haven't been bound to a register class yet) so it cheats a
bit and checks that the tokens that produced the operand are lexically
identical. This works because tied registers need to have the same register
class but it does have a flaw. It will reject 'dati $4, $a0, 1' for violating
the constraint even though $a0 ends up as the same register as $4.

Reviewers: sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: https://reviews.llvm.org/D21994

llvm-svn: 276867
2016-07-27 13:49:44 +00:00
Daniel Sanders 94ed30a401 [mips] Fix typos in spelling of lowerRETURNADDR.
The first letter was mistakenly capitalized.

llvm-svn: 276753
2016-07-26 14:46:11 +00:00
Simon Dardis 68a204ddc1 [mips] MIPS64R6 compact branch support
MIPS64R6 compact branch support. As the MIPS LLVM backend uses distinct
MachineInstrs for certain 32 and 64 bit instructions (e.g. BEQ & BEQ64) that
map to the same instruction, extend compact branch support for the
corresponding 64bit branches.

Reviewers: dsanders

Differential Revision: https://reviews.llvm.org/D20164

llvm-svn: 276739
2016-07-26 10:25:07 +00:00
Simon Dardis 273fc26b79 [mips] sgtu, s[rl]l, sra, dnegu, neg instruction aliases
Add the instruction alias sgtu (register form only), two operand forms of
s[rl]l and sra, and missing single/two operand forms of dnegu/neg.

Reviewers: dsanders

Differential Revision: https://reviews.llvm.org/D22752

llvm-svn: 276736
2016-07-26 09:13:46 +00:00
Joel Jones 373d7d30dd MC] Provide an MCTargetOptions to implementors of MCAsmBackendCtorTy, NFC
Some targets, notably AArch64 for ILP32, have different relocation encodings
based upon the ABI. This is an enabling change, so a future patch can use the
ABIName from MCTargetOptions to chose which relocations to use. Tested using
check-llvm.

The corresponding change to clang is in: http://reviews.llvm.org/D16538

Patch by: Joel Jones

Differential Revision: https://reviews.llvm.org/D16213

llvm-svn: 276654
2016-07-25 17:18:28 +00:00
Simon Dardis 618975206e [mips] Optimize materialization of i64 constants
Avoid MipsAnalyzeImmediate usage if the constant fits in an 32-bit
integer. This allows us to generate the same instructions for the
materialization of the same constants regardless the width of their
type.

Patch by: Vasileios Kalintiris

Contributions by: Simon Dardis

Reviewers: Daniel Sanders

Differential Review: https://reviews.llvm.org/D21689

llvm-svn: 276628
2016-07-25 09:57:28 +00:00
Hrvoje Varga 2db00ce4b6 [mips][microMIPS] Implement SLT, SLTI, SLTIU, SLTU microMIPS32r6 instructions
Differential Revision: https://reviews.llvm.org/D19906

llvm-svn: 276397
2016-07-22 07:18:33 +00:00
Daniel Sanders 3878412875 [mips][ias] R_MIPS_GOT_(PAGE|OFST) do not need symbols
Reviewers: sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: https://reviews.llvm.org/D22458

llvm-svn: 275968
2016-07-19 10:58:06 +00:00
Daniel Sanders 6a73883c48 [mips] Correct label prefixes for N32 and N64.
Summary:
N32 and N64 follow the standard ELF conventions (.L) whereas O32 uses its own
($).

This fixes the majority of object differences between -fintegrated-as and
-fno-integrated-as.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: https://reviews.llvm.org/D22412

llvm-svn: 275967
2016-07-19 10:49:03 +00:00
Simon Dardis d32a2d30cb [inlineasm] Propagate operand constraints to the backend
When SelectionDAGISel transforms a node representing an inline asm
block, memory constraint information is not preserved. This can cause
constraints to be broken when a memory offset is of the form:

offset + frame index

when the frame is resolved.

By propagating the constraints all the way to the backend, targets can
enforce memory operands of inline assembly to conform to their constraints.

For MIPSR6, some instructions had their offsets reduced to 9 bits from
16 bits such as ll/sc. This becomes problematic when using inline assembly
to perform atomic operations, as an offset can generated that is too big to
encode in the instruction.

Reviewers: dsanders, vkalintris

Differential Review: https://reviews.llvm.org/D21615

llvm-svn: 275786
2016-07-18 13:17:31 +00:00
Duncan P. N. Exon Smith 670900bb9e Reapply "Mips: Avoid implicit iterator conversions, NFC"
This reverts commit r275562, effectively reapplying r275141.  Doug
Gilmore reported that there was an error when bisecting the Mips
buildbot failure, and that r275141 was not to blame after all.  Here is
the green build:
https://dmz-portal.mips.com/bb/builders/LLVM%20with%20integrated%20assembler%20and%20fPIC%20and%20-O0/builds/803

llvm-svn: 275643
2016-07-15 23:09:47 +00:00
Justin Lebar 9c375817ac [SelectionDAG] Get rid of bool parameters in SelectionDAG::getLoad, getStore, and friends.
Summary:
Instead, we take a single flags arg (a bitset).

Also add a default 0 alignment, and change the order of arguments so the
alignment comes before the flags.

This greatly simplifies many callsites, and fixes a bug in
AMDGPUISelLowering, wherein the order of the args to getLoad was
inverted.  It also greatly simplifies the process of adding another flag
to getLoad.

Reviewers: chandlerc, tstellarAMD

Subscribers: jholewinski, arsenm, jyknight, dsanders, nemanjai, llvm-commits

Differential Revision: http://reviews.llvm.org/D22249

llvm-svn: 275592
2016-07-15 18:27:10 +00:00
Justin Lebar 0af80cd6f0 [CodeGen] Take a MachineMemOperand::Flags in MachineFunction::getMachineMemOperand.
Summary:
Previously we took an unsigned.

Hooray for type-safety.

Reviewers: chandlerc

Subscribers: dsanders, llvm-commits

Differential Revision: http://reviews.llvm.org/D22282

llvm-svn: 275591
2016-07-15 18:26:59 +00:00
Jacques Pienaar 71c30a14b7 Rename AnalyzeBranch* to analyzeBranch*.
Summary: NFC. Rename AnalyzeBranch/AnalyzeBranchPredicate to analyzeBranch/analyzeBranchPredicate to follow LLVM coding style and be consistent with TargetInstrInfo's analyzeCompare and analyzeSelect.

Reviewers: tstellarAMD, mcrosier

Subscribers: mcrosier, jholewinski, jfb, arsenm, dschuff, jyknight, dsanders, nemanjai

Differential Revision: https://reviews.llvm.org/D22409

llvm-svn: 275564
2016-07-15 14:41:04 +00:00
Daniel Sanders db5e666304 Revert r275141 - Mips: Avoid implicit iterator conversions, NFC
It appears to have caused some failures in our buildbots.

llvm-svn: 275562
2016-07-15 13:54:20 +00:00
Daniel Sanders 46fe6550ac [mips] SelectionDAGISel subclasses now follow the optimization level.
Summary:
It was recently discovered that, for Mips's SelectionDAGISel subclasses,
all optimization levels caused SelectionDAGISel to behave like -O2.

This change adds the necessary plumbing to initialize the optimization level.

Reviewers: andrew.w.kaylor

Subscribers: andrew.w.kaylor, sdardis, dean, llvm-commits, vradosavljevic, petarj, qcolombet, probinson, dsanders

Differential Revision: https://reviews.llvm.org/D14900

llvm-svn: 275410
2016-07-14 13:25:22 +00:00
Duncan P. N. Exon Smith fdd30c620d Mips: Avoid implicit iterator conversions, NFC
Avoid implicit conversions from MachineInstrBundleIterator to
MachineInstr* in the Mips backend, mainly by preferring MachineInstr&
over MachineInstr* when a pointer isn't nullable and using range-based
for loops.

llvm-svn: 275141
2016-07-12 01:47:02 +00:00