Commit Graph

63 Commits

Author SHA1 Message Date
Arthur Eubanks d7593ebaee [NFC] Clean up users of AttributeList::hasAttribute()
AttributeList::hasAttribute() is confusing, use clearer methods like
hasParamAttr()/hasRetAttr().

Add hasRetAttr() since it was missing from AttributeList.
2021-08-13 11:59:18 -07:00
Ayke van Laethem 4d7f5c0a85
[AVR] Only support sp, r0 and r1 in llvm.read_register
Most other registers are allocatable and therefore cannot be used.

This issue was flagged by the machine verifier, because reading other
registers is considered reading from an undefined register.

Differential Revision: https://reviews.llvm.org/D96969
2021-07-24 14:03:27 +02:00
Ayke van Laethem feda08b70a
[AVR] Do not chain stores in call frame setup
Previously, AVRTargetLowering::LowerCall attempted to keep stack stores
in order with chains. Perhaps this worked in the past, but it does not
work now: it appears that the SelectionDAG legalization phase removes
these chains. Therefore, I've removed these chains entirely to match
X86 (which, similar to AVR, also prefers to use push instructions over
stack-relative stores to set up a call frame). With this change, all the
stack stores are in a somewhat reasonable order.

Differential Revision: https://reviews.llvm.org/D97853
2021-07-24 14:03:26 +02:00
Ben Shi 22668c6e1f [AVR][NFC] Refactor 8-bit & 16-bit shifts
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D98335
2021-05-31 10:30:46 +08:00
Ben Shi 86812faa5f [AVR] Improve inline assembly
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D96394
2021-05-30 23:44:43 +08:00
Dylan McKay 83e2710eb0 [AVR] Remove an assertion that causes generic CodeGen tests to fail
It was discussed a few years ago and agreed that it makes sense to
remove this assertion as other targets do not perform similar register
size checking in inline assembly constraint logic, so the check just
adds a needless barrier on AVR.

This patch removes the assertion and removes 'XFAIL' from two Generic
CodeGen tests for AVR as a result.
2021-02-05 02:05:23 +13:00
Kazu Hirata 8ed1636184 [llvm] Use isa instead of dyn_cast (NFC) 2021-01-29 23:23:37 -08:00
Ben Shi 50f1aa1db5 [AVR] Optimize 16-bit int shift
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D90092
2021-01-28 15:10:11 +08:00
Ben Shi 2a4acf3ea8 [AVR] Optimize 8-bit int shift
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D90678
2021-01-24 11:04:37 +08:00
Ben Shi 1eb8c5cd35 [AVR] Optimize 16-bit comparison with constant
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D93976
2021-01-24 00:38:57 +08:00
Ben Shi 25531a1d96 [AVR] Optimize 8-bit logic left/right shifts
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D89047
2021-01-23 23:54:16 +08:00
Ayke van Laethem e03ba2198d
[AVR] Improve inline rotate/shift expansions
These expansions were rather inefficient and were done with more code
than necessary. This change optimizes them to use expansions more
similar to GCC. The code size is the same (when optimizing for code
size) but somehow LLVM reorders blocks in a non-optimal way. Still, this
should be an improvement with a reduction in code size of around 0.12%
(when building compiler-rt).

Differential Revision: https://reviews.llvm.org/D86418
2020-10-31 23:15:49 +01:00
Craig Topper c193a689b4 [SelectionDAG] Use Align/MaybeAlign in calls to getLoad/getStore/getExtLoad/getTruncStore.
The versions that take 'unsigned' will be removed in the future.

I tried to use getOriginalAlign instead of getAlign in some
places. getAlign factors in the minimum alignment implied by
the offset in the pointer info. Since we're also passing the
pointer info we can use the original alignment.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D87592
2020-09-14 13:54:50 -07:00
Dylan McKay b9c26a9cfe [AVR] Rewrite the function calling convention.
Summary:
The previous version relied on the standard calling convention using
std::reverse() to try to force the AVR ABI. But this only works for
simple cases, it fails for example with aggregate types.

This patch rewrites the calling convention with custom C++ code, that
implements the ABI defined in https://gcc.gnu.org/wiki/avr-gcc.

To do that it adds a few 16-bit pseudo registers for unaligned argument
passing, such as R24R23. For example this function:

    define void @fun({ i8, i16 } %a)

will pass %a.0 in R22 and %a.1 in R24R23.

There are no instructions that can use these pseudo registers, so a new
register class, DREGSMOVW, is defined to make them apart.

Also the ArgCC_AVR_BUILTIN_DIV is no longer necessary, as it is
identical to the C++ behavior (actually the clobber list is more strict
for __div* functions, but that is currently unimplemented).

Reviewers: dylanmckay

Subscribers: Gaelan, Sh4rK, indirect, jwagen, efriedma, dsprenkels, hiraditya, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68524

Patch by Rodrigo Rivas Costa.
2020-06-23 21:36:18 +12:00
Guillaume Chatelet 1778564f91 [Alignment][NFC] Migrate the rest of backends
Summary: This is a followup on D81196

Reviewers: courbet

Subscribers: arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81278
2020-06-08 07:17:20 +00:00
Ayke van Laethem 9505b5cb66
[AVR] Do not use divmod calls for bigger integers
The avr-libc provides *divmodqi4, *divmodhi4, and *divmodsi4 functions,
but does not provide a *divmoddi4. Instead it provides regular *divdi3
and *moddi3 functions.

Note that avr-libc doesn't support *divti3 or *modti3 for 128-bit
integer manipulation.

Source:
https://github.com/gcc-mirror/gcc/blob/releases/gcc-5.4.0/libgcc/config/avr/lib1funcs.S

Differential Revision: https://reviews.llvm.org/D78437
2020-04-20 13:56:38 +02:00
Dylan McKay 7b808b105f [AVR] Generalize the previous interrupt bugfix to signal handlers too 2020-03-31 19:33:34 +13:00
Dylan McKay 339b34266c [AVR] Respect the 'interrupt' function attribute
In the past, AVR functions were only lowered with interrupt-specific
machine code if the function was defined with the "avr-interrupt" or
"avr-signal" calling conventions.

This patch modifies the backend so that if the function does not have a
special calling convention, but does have an "interrupt" attribute,
that function is interpreted as a function with interrupts.

This also extracts the "is this function an interrupt" logic from
several disparate places in the backend into one AVRMachineFunctionInfo
attribute.

Bug found by Wilhelm Meier.
2020-03-31 19:00:18 +13:00
Simon Pilgrim 68224c1952 [TargetLowering] Only demand a rotation's modulo amount bits
ISD::ROTL/ROTR rotation values are guaranteed to act as a modulo amount, so for power-of-2 bitwidths we only need the lowest bits.

Differential Revision: https://reviews.llvm.org/D76201
2020-03-17 21:23:46 +00:00
Jim Lin ea6eb813c7 [AVR][NFC] Use Register instead of unsigned
Summary: Use Register type for variables instead of unsigned type.

Reviewers: dylanmckay

Reviewed By: dylanmckay

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75595
2020-03-05 11:38:24 +08:00
Jim Lin c0a2da9460 [AVR] Add missing ROLLOOP and RORLOOP into getTargetNodeName 2020-03-03 09:43:52 +08:00
Matt Arsenault 5fe4679cc9 AVR: Update for getRegisterByName change 2020-01-09 18:28:10 -05:00
Jim Lin da0fe5db99 [AVR] Fix codegen for rotate instructions
Summary:
    This patch introduces the ROLBRd and RORBRd pseudo-instructions,
    which implemenent the "traditional" rotate operations; instead of
    the AVR rotate instructions that use the carry bit.

    The code is not optimized at all. Especially when dealing with
    loops of rotate instructions, this codegen should be improved some
    day.

Related bug: 41358 <https://bugs.llvm.org/show_bug.cgi?id=41358>

//Note//: This is my first submitted patch.

Reviewers: dylanmckay, Jim

Reviewed By: dylanmckay

Subscribers: hiraditya, llvm-commits, dylanmckay, dsprenkels

Tags: #llvm

Patched by dsprenkels (Daan Sprenkels)

Differential Revision: https://reviews.llvm.org/D60365
2019-12-23 11:41:28 +08:00
Matt Arsenault f24ac13aaa TLI: Remove DAG argument from getRegisterByName
Replace with the MachineFunction. X86 is the only user, and only uses
it for the function. This removes one obstacle from using this in
GlobalISel. The other is the more tolerable EVT argument.

The X86 use of the function seems questionable to me. It checks hasFP,
before frame lowering.

llvm-svn: 373292
2019-10-01 01:44:39 +00:00
Guillaume Chatelet 18f805a7ea [Alignment][NFC] Remove unneeded llvm:: scoping on Align types
llvm-svn: 373081
2019-09-27 12:54:21 +00:00
Sylvestre Ledru 112f145306 Replicate the change "[Alignment][NFC] Use Align with TargetLowering::setMinFunctionAlignment"
on AVR to avoid a breakage.
See r371200 / https://reviews.llvm.org/D67229

llvm-svn: 371293
2019-09-07 08:38:46 +00:00
Guillaume Chatelet aff45e4b23 [LLVM][Alignment] Make functions using log of alignment explicit
Summary:
This patch renames functions that takes or returns alignment as log2, this patch will help with the transition to llvm::Align.
The renaming makes it explicit that we deal with log(alignment) instead of a power of two alignment.
A few renames uncovered dubious assignments:

 - `MirParser`/`MirPrinter` was expecting powers of two but `MachineFunction` and `MachineBasicBlock` were using deal with log2(align). This patch fixes it and updates the documentation.
 - `MachineBlockPlacement` exposes two flags (`align-all-blocks` and `align-all-nofallthru-blocks`) supposedly interpreted as power of two alignments, internally these values are interpreted as log2(align). This patch updates the documentation,
 - `MachineFunctionexposes` exposes `align-all-functions` also interpreted as power of two alignment, internally this value is interpreted as log2(align). This patch updates the documentation,

Reviewers: lattner, thegameg, courbet

Subscribers: dschuff, arsenm, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, Jim, s.egerton, llvm-commits, courbet

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65945

llvm-svn: 371045
2019-09-05 10:00:22 +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
Bill Wendling 41a2847a9a Emit diagnostic if an inline asm constraint requires an immediate
Summary:
An inline asm call can result in an immediate after inlining. Therefore emit a
diagnostic here if constraint requires an immediate but one isn't supplied.

Reviewers: joerg, mgorny, efriedma, rsmith

Reviewed By: joerg

Subscribers: asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, s.egerton, MaskRay, jyknight, dylanmckay, javed.absar, fedor.sergeev, jrtc27, Jim, krytarowski, eraman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60942

llvm-svn: 367750
2019-08-03 05:52:47 +00:00
Evandro Menezes 567f6c150d [AVR] Change limit type to match the argument type (NFC)
llvm-svn: 363832
2019-06-19 16:12:12 +00:00
Dylan McKay 04b418f246 [AVR] Expand 16-bit rotations during the legalization stage
In r356860, the legalization logic for BSWAP was modified to ISD::ROTL,
rather than the old ISD::{SHL, SRL, OR} nodes.

This works fine on AVR for 8-bit rotations, but 16-bit rotations are
currently unimplemented - they always trigger an assertion error in the
AVRExpandPseudoInsts pass ("RORW unimplemented").

This patch instructions the legalizer to expand 16-bit rotations into
the previous SHL, SRL, OR pattern it did previously.

This fixes the 'issue-cannot-select-bswap.ll' test. Interestingly, this
test failure seems flaky - it passes successfully on the avr-build-01
buildbot, but fails locally on my Arch Linux install.

llvm-svn: 362773
2019-06-07 06:55:00 +00:00
Dylan McKay 8a56d10a2f [AVR] Fix a typo - 's/analisys/analysis'
llvm-svn: 353987
2019-02-13 22:31:37 +00:00
Dylan McKay 5c23410fdf [AVR] Insert unconditional branch when inserting MBBs between blocks with fallthrough
This updates the AVR Select8/Select16 expansion code so that, when
inserting the two basic blocks for true and false conditions, any
existing fallthrough on the previous block is preserved.

Prior to this patch, if the block before the Select pseudo fell through
to the subsequent block, two new basic blocks would be inserted at the
prior fallthrough point, changing the fallthrough destination.

The predecessor or successor lists were not updated, causing the
BranchFolding pass at -O1 and above the rearrange basic blocks, causing
an infinite loop. Not to mention the unconditional fallthrough to the
true block is incorrect in of itself.

This patch modifies the Select8/16 expansion so that, if inserting true
and false basic blocks at a fallthrough point, the implicit branch is
preserved by means of an explicit, unconditional branch to the previous
fallthrough destination.

Thanks to Carl Peto for reporting this bug.

This fixes avr-rust bug https://github.com/avr-rust/rust/issues/123.

llvm-svn: 351721
2019-01-21 04:32:02 +00:00
Dylan McKay ce0ab06353 Revert "[AVR] Insert unconditional branch when inserting MBBs between blocks with fallthrough"
This reverts commit r351718.

Carl pointed out that the unit test could be improved.

This patch will be recommitted once the test is made more resilient.

llvm-svn: 351719
2019-01-21 02:46:13 +00:00
Dylan McKay 33acba43f0 [AVR] Insert unconditional branch when inserting MBBs between blocks with fallthrough
This updates the AVR Select8/Select16 expansion code so that, when
inserting the two basic blocks for true and false conditions, any
existing fallthrough on the previous block is preserved.

Prior to this patch, if the block before the Select pseudo fell through
to the subsequent block, two new basic blocks would be inserted at the
prior fallthrough point, changing the fallthrough destination.

The predecessor or successor lists were not updated, causing the
BranchFolding pass at -O1 and above the rearrange basic blocks, causing
an infinite loop. Not to mention the unconditional fallthrough to the
true block is incorrect in of itself.

This patch modifies the Select8/16 expansion so that, if inserting true
and false basic blocks at a fallthrough point, the implicit branch is
preserved by means of an explicit, unconditional branch to the previous
fallthrough destination.

Thanks to Carl Peto for reporting this bug.

This fixes avr-rust bug https://github.com/avr-rust/rust/issues/123.

llvm-svn: 351718
2019-01-21 02:44:09 +00:00
Dylan McKay 6afef286d9 [AVR] Fix codegen bug in 16-bit loads
Prior to this patch, the AVR::LDWRdPtr instruction was always lowered to
instructions of this pattern:

    ld  $GPR8, [PTR:XYZ]+
    ld  $GPR8, [PTR]+1

This has a problem; the [PTR] is incremented in-place once, but never
decremented.

Future uses of the same pointer will use the now clobbered value,
leading to the pointer being incorrect by an offset of one.

This patch modifies the expansion code of the LDWRdPtr pseudo
instruction so that the pointer variable is not silently clobbered in
future uses in the same live range.

Bug first reported by Keshav Kini.

Patch by Kaushik Phatak.

llvm-svn: 351673
2019-01-20 03:41:08 +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
Dylan McKay 7203e00b5e [AVR] Expand 8/16-bit multiplication to libcalls on MCUs that don't have hardware MUL
This change modifies the LLVM ISel lowering settings so that
8-bit/16-bit multiplication is expanded to calls into the compiler
runtime library if the MCU being targeted does not support
multiplication in hardware.

Before this, MUL instructions would be generated on CPUs like the
ATtiny85, triggering a CPU reset due to an illegal instruction at
runtime.

First raised in https://github.com/avr-rust/rust/issues/124.

llvm-svn: 351523
2019-01-18 06:10:41 +00:00
Dylan McKay 454258671d [AVR] Redefine the 'LSL' instruction as an alias of 'ADD'
The 'LSL Rd' instruction is equivalent to 'ADD Rd, Rd'.

llvm-svn: 341278
2018-09-01 12:23:00 +00:00
Dylan McKay 8b0f9d2e58 [AVR] Define the ROL instruction as an alias of ADC
The 'rol Rd' instruction is equivalent to 'adc Rd'.

This caused compile warnings from tablegen because of conflicting bits
shared between each instruction.

llvm-svn: 341275
2018-09-01 12:22:07 +00:00
Dylan McKay 6bc5d5c6db [AVR] Re-enable expansion of ADDE/ADDC/SUBE/SUBC in ISel
This was disabled in r333748, which broke four tests.

In the future, these need to be updated to UADDO/ADDCARRY or
USUBO/SUBCARRY.

llvm-svn: 338212
2018-07-29 11:38:36 +00:00
Dylan McKay a35ee70641 [AVR] Lower i128 divisions to runtime library calls
This patch adds i128 division support by instruction LLVM to lower
128-bit divisions to the __udivmodti4 and __divmodti4 rtlib functions.

This also adds test for 64-bit division and 128-bit division.

Patch by Peter Nimmervoll.

llvm-svn: 327814
2018-03-19 00:55:50 +00:00
Dylan McKay 05d3e41076 [AVR] Fix a lowering bug in AVRISelLowering.cpp
The parseFunctionArgs() method was directly reading the
arguments from a Function object, but is should have used the
arguments supplied by the SelectionDAGBuilder.

This was causing
the lowering code to only lower one argument, not two in some cases.

Thanks to @brainlag on GitHub for coming up with the working fix!

Patch-by: @brainlag on GitHub
llvm-svn: 325474
2018-02-19 08:28:38 +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
Dylan McKay 80463fe64d Relax unaligned access assertion when type is byte aligned
Summary:
This relaxes an assertion inside SelectionDAGBuilder which is overly
restrictive on targets which have no concept of alignment (such as AVR).

In these architectures, all types are aligned to 8-bits.

After this, LLVM will only assert that accesses are aligned on targets
which actually require alignment.

This patch follows from a discussion on llvm-dev a few months ago
http://llvm.1065342.n5.nabble.com/llvm-dev-Unaligned-atomic-load-store-td112815.html

Reviewers: bogner, nemanjai, joerg, efriedma

Reviewed By: efriedma

Subscribers: efriedma, cactus, llvm-commits

Differential Revision: https://reviews.llvm.org/D39946

llvm-svn: 320243
2017-12-09 06:45:36 +00:00
Dylan McKay 1446eedbc2 [AVR] Prefer BasicBlock::getIterator over Function::begin()
Thanks to Eli Friedman for the suggestion.

llvm-svn: 314182
2017-09-26 01:37:53 +00:00
Dylan McKay dada014781 [AVR] When lowering shifts into loops, put newly generated MBBs in the same
spot as the original MBB

Discovered in avr-rust/rust#62
https://github.com/avr-rust/rust/issues/62

Patch by Gergo Erdi.

llvm-svn: 314180
2017-09-26 00:51:03 +00:00
Jonas Paulsson 024e319489 [SystemZ, LoopStrengthReduce]
This patch makes LSR generate better code for SystemZ in the cases of memory
intrinsics, Load->Store pairs or comparison of immediate with memory.

In order to achieve this, the following common code changes were made:

 * New TTI hook: LSRWithInstrQueries(), which defaults to false. Controls if
 LSR should do instruction-based addressing evaluations by calling
 isLegalAddressingMode() with the Instruction pointers.
 * In LoopStrengthReduce: handle address operands of memset, memmove and memcpy
 as address uses, and call isFoldableMemAccessOffset() for any LSRUse::Address,
 not just loads or stores.

SystemZ changes:

 * isLSRCostLess() implemented with Insns first, and without ImmCost.
 * New function supportedAddressingMode() that is a helper for TTI methods
 looking at Instructions passed via pointers.

Review: Ulrich Weigand, Quentin Colombet
https://reviews.llvm.org/D35262
https://reviews.llvm.org/D35049

llvm-svn: 308729
2017-07-21 11:59:37 +00:00
Dylan McKay 043fa4b3d6 [AVR] Fix a big in shift operator lowering; Authored by Dr. Gergo Erdi
When generating code for a shift loop, check the shift
 amount against the literal value 0, not R0

llvm-svn: 304284
2017-05-31 06:27:46 +00:00
Dylan McKay 0c4debc123 [AVR] When lowering Select8/Select16, put newly generated MBBs in the same spot
Contributed by Dr. Gergő Érdi.

Fixes a bug.

Raised from (https://github.com/avr-rust/rust/issues/49).

llvm-svn: 302973
2017-05-13 00:22:34 +00:00