This adds initial support for PPC32 ELF PIC (Position Independent Code; the
-fPIC variety), thus rectifying a long-standing deficiency in the PowerPC
backend.
Patch by Justin Hibbits!
llvm-svn: 213427
During an indirect function call sequence on the 64-bit SVR4 ABI,
generate code must load and then restore the TOC register.
This does not use a regular LOAD instruction since the TOC
register r2 is marked as reserved. Instead, the are two
special instruction patterns:
let RST = 2, DS = 2 in
def LDinto_toc: DSForm_1a<58, 0, (outs), (ins g8rc:$reg),
"ld 2, 8($reg)", IIC_LdStLD,
[(PPCload_toc i64:$reg)]>, isPPC64;
let RST = 2, DS = 10, RA = 1 in
def LDtoc_restore : DSForm_1a<58, 0, (outs), (ins),
"ld 2, 40(1)", IIC_LdStLD,
[(PPCtoc_restore)]>, isPPC64;
Note that these not only restrict the destination of the
load to r2, but they also restrict the *source* of the
load to particular address combinations. The latter is
a problem when we want to support the ELFv2 ABI, since
there the TOC save slot is no longer at 40(1).
This patch replaces those two instructions with a single
instruction pattern that only hard-codes r2 as destination,
but supports generic addresses as source. This will allow
supporting the ELFv2 ABI, and also helps generate more
efficient code for calls to absolute addresses (allowing
simplification of the ppc64-calls.ll test case).
llvm-svn: 211193
I'm under the impression that we used to infer the isCommutable flag from the
instruction-associated pattern. Regardless, we don't seem to do this (at least
by default) any more. I've gone through all of our instruction definitions, and
marked as commutative all of those that should be trivial to commute (by
exchanging the first two operands). There has been special code for the RL*
instructions, and that's not changed.
Before this change, we had the following commutative instructions:
RLDIMI
RLDIMIo
RLWIMI
RLWIMI8
RLWIMI8o
RLWIMIo
XSADDDP
XSMULDP
XVADDDP
XVADDSP
XVMULDP
XVMULSP
After:
ADD4
ADD4o
ADD8
ADD8o
ADDC
ADDC8
ADDC8o
ADDCo
ADDE
ADDE8
ADDE8o
ADDEo
AND
AND8
AND8o
ANDo
CRAND
CREQV
CRNAND
CRNOR
CROR
CRXOR
EQV
EQV8
EQV8o
EQVo
FADD
FADDS
FADDSo
FADDo
FMADD
FMADDS
FMADDSo
FMADDo
FMSUB
FMSUBS
FMSUBSo
FMSUBo
FMUL
FMULS
FMULSo
FMULo
FNMADD
FNMADDS
FNMADDSo
FNMADDo
FNMSUB
FNMSUBS
FNMSUBSo
FNMSUBo
MULHD
MULHDU
MULHDUo
MULHDo
MULHW
MULHWU
MULHWUo
MULHWo
MULLD
MULLDo
MULLW
MULLWo
NAND
NAND8
NAND8o
NANDo
NOR
NOR8
NOR8o
NORo
OR
OR8
OR8o
ORo
RLDIMI
RLDIMIo
RLWIMI
RLWIMI8
RLWIMI8o
RLWIMIo
VADDCUW
VADDFP
VADDSBS
VADDSHS
VADDSWS
VADDUBM
VADDUBS
VADDUHM
VADDUHS
VADDUWM
VADDUWS
VAND
VAVGSB
VAVGSH
VAVGSW
VAVGUB
VAVGUH
VAVGUW
VMADDFP
VMAXFP
VMAXSB
VMAXSH
VMAXSW
VMAXUB
VMAXUH
VMAXUW
VMHADDSHS
VMHRADDSHS
VMINFP
VMINSB
VMINSH
VMINSW
VMINUB
VMINUH
VMINUW
VMLADDUHM
VMULESB
VMULESH
VMULEUB
VMULEUH
VMULOSB
VMULOSH
VMULOUB
VMULOUH
VNMSUBFP
VOR
VXOR
XOR
XOR8
XOR8o
XORo
XSADDDP
XSMADDADP
XSMAXDP
XSMINDP
XSMSUBADP
XSMULDP
XSNMADDADP
XSNMSUBADP
XVADDDP
XVADDSP
XVMADDADP
XVMADDASP
XVMAXDP
XVMAXSP
XVMINDP
XVMINSP
XVMSUBADP
XVMSUBASP
XVMULDP
XVMULSP
XVNMADDADP
XVNMADDASP
XVNMSUBADP
XVNMSUBASP
XXLAND
XXLNOR
XXLOR
XXLXOR
This is a by-inspection change, and I'm not sure how to write a reliable test
case. I would like advice on this, however.
llvm-svn: 204609
VSX is an ISA extension supported on the POWER7 and later cores that enhances
floating-point vector and scalar capabilities. Among other things, this adds
<2 x double> support and generally helps to reduce register pressure.
The interesting part of this ISA feature is the register configuration: there
are 64 new 128-bit vector registers, the 32 of which are super-registers of the
existing 32 scalar floating-point registers, and the second 32 of which overlap
with the 32 Altivec vector registers. This makes things like vector insertion
and extraction tricky: this can be free but only if we force a restriction to
the right register subclass when needed. A new "minipass" PPCVSXCopy takes care
of this (although it could do a more-optimal job of it; see the comment about
unnecessary copies below).
Please note that, currently, VSX is not enabled by default when targeting
anything because it is not yet ready for that. The assembler and disassembler
are fully implemented and tested. However:
- CodeGen support causes miscompiles; test-suite runtime failures:
MultiSource/Benchmarks/FreeBench/distray/distray
MultiSource/Benchmarks/McCat/08-main/main
MultiSource/Benchmarks/Olden/voronoi/voronoi
MultiSource/Benchmarks/mafft/pairlocalalign
MultiSource/Benchmarks/tramp3d-v4/tramp3d-v4
SingleSource/Benchmarks/CoyoteBench/almabench
SingleSource/Benchmarks/Misc/matmul_f64_4x4
- The lowering currently falls back to using Altivec instructions far more
than it should. Worse, there are some things that are scalarized through the
stack that shouldn't be.
- A lot of unnecessary copies make it past the optimizers, and this needs to
be fixed.
- Many more regression tests are needed.
Normally, I'd fix these things prior to committing, but there are some
students and other contributors who would like to work this, and so it makes
sense to move this development process upstream where it can be subject to the
regular code-review procedures.
llvm-svn: 203768
This change enables tracking i1 values in the PowerPC backend using the
condition register bits. These bits can be treated on PowerPC as separate
registers; individual bit operations (and, or, xor, etc.) are supported.
Tracking booleans in CR bits has several advantages:
- Reduction in register pressure (because we no longer need GPRs to store
boolean values).
- Logical operations on booleans can be handled more efficiently; we used to
have to move all results from comparisons into GPRs, perform promoted
logical operations in GPRs, and then move the result back into condition
register bits to be used by conditional branches. This can be very
inefficient, because the throughput of these CR <-> GPR moves have high
latency and low throughput (especially when other associated instructions
are accounted for).
- On the POWER7 and similar cores, we can increase total throughput by using
the CR bits. CR bit operations have a dedicated functional unit.
Most of this is more-or-less mechanical: Adjustments were needed in the
calling-convention code, support was added for spilling/restoring individual
condition-register bits, and conditional branch instruction definitions taking
specific CR bits were added (plus patterns and code for generating bit-level
operations).
This is enabled by default when running at -O2 and higher. For -O0 and -O1,
where the ability to debug is more important, this feature is disabled by
default. Individual CR bits do not have assigned DWARF register numbers,
and storing values in CR bits makes them invisible to the debugger.
It is critical, however, that we don't move i1 values that have been promoted
to larger values (such as those passed as function arguments) into bit
registers only to quickly turn around and move the values back into GPRs (such
as happens when values are returned by functions). A pair of target-specific
DAG combines are added to remove the trunc/extends in:
trunc(binary-ops(binary-ops(zext(x), zext(y)), ...)
and:
zext(binary-ops(binary-ops(trunc(x), trunc(y)), ...)
In short, we only want to use CR bits where some of the i1 values come from
comparisons or are used by conditional branches or selects. To put it another
way, if we can do the entire i1 computation in GPRs, then we probably should
(on the POWER7, the GPR-operation throughput is higher, and for all cores, the
CR <-> GPR moves are expensive).
POWER7 test-suite performance results (from 10 runs in each configuration):
SingleSource/Benchmarks/Misc/mandel-2: 35% speedup
MultiSource/Benchmarks/Prolangs-C++/city/city: 21% speedup
MultiSource/Benchmarks/MiBench/automotive-susan: 23% speedup
SingleSource/Benchmarks/CoyoteBench/huffbench: 13% speedup
SingleSource/Benchmarks/Misc-C++/Large/sphereflake: 13% speedup
SingleSource/Benchmarks/Misc-C++/mandel-text: 10% speedup
SingleSource/Benchmarks/Misc-C++-EH/spirit: 10% slowdown
MultiSource/Applications/lemon/lemon: 8% slowdown
llvm-svn: 202451
My understanding (from reading just the llvm code) is that
* most ppc cpus have a "sync n" instruction and an msync alias that is "sync 0".
* "book e" cpus instead have a msync instruction and not the more
general "sync n"
This patch reflects that in the .td files, allowing a single codepath for
asm ond obj streamer and incidentelly fixes a crash when EmitRawText was
called on a obj streamer.
llvm-svn: 199832
Several of the 64-bit fixed-point instructions with immediate operands were
using the 32-bit (i32) operand nodes instead of the corresponding 64-bit (i64)
operand definitions (u16imm instead of u16imm64, for example).
This error has had no effect so far, but would have caused type-checking
violations with an upcoming change.
llvm-svn: 198356
The tests for the disassembler were adapted from the encoder tests, and for the
most part, the output from the disassembler matches that encoder-test inputs.
There are some places where more-informative mnemonics could be produced
(notably for the branch instructions), and those cases are noted in the tests
with FIXMEs.
Future work includes:
- Generating more-informative mnemonics when possible (this may also be done
in the printer).
- Remove the dependence on positional "numbered" operand-to-variable mapping
(for both encoding and decoding).
- Internally using 64-bit instruction variants in 64-bit mode (if this turns
out to matter).
llvm-svn: 197693
The instruction definitions in the PPC backend have a number of variants
defined for the same instruction to represent differences between 64-bit and
32-bit semantics. In order to generate a disassembler for the PPC backend, we
need to mark all but one of these as CodeGen only.
No functionality change intended; this is prep work for PPC disassembly
support.
llvm-svn: 197535
Aside from a few minor latency corrections, the major change here is a new
hazard recognizer which focuses on better dispatch-group formation on the
POWER7. As with the PPC970's hazard recognizer, the most important thing it
does is avoid load-after-store hazards within the same dispatch group. It uses
the POWER7's special dispatch-group-terminating nop instruction (instead of
inserting multiple regular nop instructions). This new hazard recognizer makes
use of the scheduling dependency graph itself, built using AA information, to
robustly detect the possibility of load-after-store hazards.
significant test-suite performance changes (the error bars are 99.5% confidence
intervals based on 5 test-suite runs both with and without the change --
speedups are negative):
speedups:
MultiSource/Benchmarks/FreeBench/pcompress2/pcompress2
-0.55171% +/- 0.333168%
MultiSource/Benchmarks/TSVC/CrossingThresholds-dbl/CrossingThresholds-dbl
-17.5576% +/- 14.598%
MultiSource/Benchmarks/TSVC/Reductions-dbl/Reductions-dbl
-29.5708% +/- 7.09058%
MultiSource/Benchmarks/TSVC/Reductions-flt/Reductions-flt
-34.9471% +/- 11.4391%
SingleSource/Benchmarks/BenchmarkGame/puzzle
-25.1347% +/- 11.0104%
SingleSource/Benchmarks/Misc/flops-8
-17.7297% +/- 9.79061%
SingleSource/Benchmarks/Shootout-C++/ary3
-35.5018% +/- 23.9458%
SingleSource/Regression/C/uint64_to_float
-56.3165% +/- 25.4234%
SingleSource/UnitTests/Vectorizer/gcc-loops
-18.5309% +/- 6.8496%
regressions:
MultiSource/Benchmarks/ASCI_Purple/SMG2000/smg2000
18.351% +/- 12.156%
SingleSource/Benchmarks/Shootout-C++/methcall
27.3086% +/- 14.4733%
llvm-svn: 197099
In preparation for adding scheduling definitions for the POWER7, split some PPC
itinerary classes so that the P7's latencies and hazards can be better
described. For the most part, this means differentiating indexed from non-index
pre-increment loads and stores. Also, differentiate single from
double-precision sqrt.
No functionality change intended (except for a more-specific latency for
single-precision sqrt on the A2).
llvm-svn: 195980
This adds the IIC_ prefix to the instruction itinerary class names, giving the
PPC backend a naming convention for itinerary classes that is more consistent
with that used by the X86 and ARM backends.
Instruction scheduling in the PPC backend needs a bunch of cleanup and
improvement (especially for the ooo cores). This is just a preliminary step.
No functionality change intended.
llvm-svn: 195890
Use the new instruction deprecation feature to mark mftb (now replaced with
mfspr) and dst (along with the other Altivec cache control instructions) as
deprecated when targeting cores supporting at least ISA v2.03.
llvm-svn: 190605
Aggressive anti-dependency breaking is enabled by default for all PPC cores.
This provides a general speedup on the P7 and other platforms (among other
factors, the instruction group formation for the non-embedded PPC cores is done
during post-RA scheduling). In order to do this safely, the incompatibility
between uses of the MFOCRF instruction and anti-dependency breaking are
resolved by marking MFOCRF with hasExtraSrcRegAllocReq. As noted in the removed
FIXME, the problem was that MFOCRF's output is sensitive to the identify of the
source register, and always paired with a shift to undo this effect. Because
anti-dependency breaking is unaware of this hidden dependency of the shift
amount on the source register of the MFOCRF instruction, changing that register
must be inhibited.
Two test cases were adjusted: The SjLj test was made more insensitive to
register choices and scheduling; the saveCR test disabled anti-dependency
breaking because part of what it is testing is proper register reuse.
llvm-svn: 190587
Modern PPC cores support a floating-point copysign instruction, and we can use
this to lower the FCOPYSIGN node (which is created from calls to the libm
copysign function). A couple of extra patterns are necessary because the
operand types of FCOPYSIGN need not agree.
llvm-svn: 188653
Making use of the recently-added ISD::FROUND, which allows for custom lowering
of round(), the PPC backend will now map frin to round(). Previously, we had
been using frin to lower nearbyint() (and rint() via some custom lowering to
handle the extra fenv flags requirements), but only in fast-math mode because
frin does not tie-to-even. Several users had complained about this behavior,
and this new mapping of frin to round is certainly more appropriate (and does
not require fast-math mode).
In effect, this reverts r178362 (and part of r178337, replacing the nearbyint
mapping with the round mapping).
llvm-svn: 187960
Because the builtin longjmp implementation uses a CTR-based indirect jump, when
the control flow arrives at the builtin setjmp call, the CTR register has
necessarily been clobbered. Correspondingly, this adds CTR to the list of
implicit definitions of the builtin setjmp pseudo instruction.
We don't need to add CTR to the implicit definitions of builtin longjmp
because, even though it does clobber the CTR register, the control flow cannot
return to inside the loop unless there is also a builtin setjmp call.
llvm-svn: 186488
This adds support for the old-style time base instructions;
while new programs are supposed to use mfspr, the mftb instructions
are still supported and in use by existing assembler files.
llvm-svn: 185829
This adds support for the basic mnemoics (with the L operand) for the
fixed-point compare instructions. These are defined as aliases for the
already existing CMPW/CMPD patterns, depending on the value of L.
This requires use of InstAlias patterns with immediate literal operands.
To make this work, we need two further changes:
- define a RegisterPrefix, because otherwise literals 0 and 1 would
be parsed as literal register names
- provide a PPCAsmParser::validateTargetOperandClass routine to
recognize immediate literals (like ARM does)
llvm-svn: 185826
This adds support for specifying condition registers and
condition register fields via expressions using the symbols
defined by the PowerISA, like "4*cr2+eq".
llvm-svn: 185633
Just as with mfocrf, it is also preferable to use mtocrf instead of
mtcrf when only a single CR register is to be written.
Current code however always emits mtcrf. This probably does not matter
when using an external assembler, since the GNU assembler will in fact
automatically replace mtcrf with mtocrf when possible. It does create
inefficient code with the integrated assembler, however.
To fix this, this patch adds MTOCRF/MTOCRF8 instruction patterns and
uses those instead of MTCRF/MTCRF8 everything. Just as done in the
MFOCRF patch committed as 185556, these patterns will be converted
back to MTCRF if MTOCRF is not available on the machine.
As a side effect, this allows to modify the MTCRF pattern to accept
the full range of mask operands for the benefit of the asm parser.
llvm-svn: 185561
When accessing just a single CR register, it is always preferable to
use mfocrf instead of mfcr, if the former is available on the CPU.
Current code makes that distinction in many, but not all places
where a single CR register value is retrieved. One missing
location is PPCRegisterInfo::lowerCRSpilling.
To fix this and make this simpler in the future, this patch changes
the bulk of the back-end to always assume mfocrf is available and
simply generate it when needed.
On machines that actually do not support mfocrf, the instruction
is replaced by mfcr at the very end, in EmitInstruction.
This has the additional benefit that we no longer need the
MFCRpseud hack, since before EmitInstruction we always have
a MFOCRF instruction pattern, which already models data flow
as required.
The patch also adds the MFOCRF8 version of the instruction,
which was missing so far.
Except for the PPCRegisterInfo::lowerCRSpilling case, no change
in generated code intended.
llvm-svn: 185556
This adds support for the generic forms of mtspr/mfspr
for the asm parser. The compiler will continue to use
the specialized patters for mtlr etc. since those are
needed to correctly describe data flow.
llvm-svn: 185532
The assembler currently strictly verifies that immediates for
s16imm operands are in range (-32768 ... 32767). This matches
the behaviour of the GNU assembler, with one exception: gas
allows, as a special case, operands in an extended range
(-65536 .. 65535) for the addis instruction only (and its
extended mnemonic lis).
The main reason for this seems to be to allow using unsigned
16-bit operands for lis, e.g. like lis %r1, 0xfedc.
Since this has been supported by gas for a long time, and
assembler source code seen "in the wild" actually exploits
this feature, this patch adds equivalent support to LLVM
for compatibility reasons.
llvm-svn: 184946
Currently, all instructions taking s16imm operands support symbolic
operands. However, for u16imm operands, we only support actual
immediate integers. This causes the assembler to reject code like
ori %r5, %r5, symbol@l
This patch changes the u16imm operand definition to likewise
accept symbolic operands. In fact, s16imm and u16imm can
share the same encoding routine, now renamed to getImm16Encoding.
llvm-svn: 184944
This adds support for the predicted forms of branches (+/-).
There are three cases to consider:
- Branches using a PPC::Predicate code
For these, I've added new PPC::Predicate codes corresponding
to the BO values for predicted branch forms, and updated insn
printing to print them correctly. I've also added new aliases
for the asm parser matching the new forms.
- bt/bf
I've added new aliases matching to gBC etc.
- bd(n)z variants
I've added new instruction patterns for the predicted forms.
In all cases, the new patterns are used for the asm parser only.
(The new infrastructure ought to be sufficient to allow use by
the compiler too at some point.)
llvm-svn: 184754
This adds instruction patterns to cover the generic forms of
the conditional branch instructions. This allows the assembler
to support the generic mnemonics.
The compiler will still generate the various specific forms
of the instruction that were already supported.
llvm-svn: 184722
There is currently only limited support for the "absolute" variants
of branch instructions. This patch adds support for the absolute
variants of all branches that are currently otherwise supported.
This requires adding new fixup types so that the correct variant
of relocation type can be selected by the object writer.
While the compiler will continue to usually choose the relative
branch variants, this will allow the asm parser to fully support
the absolute branches, with either immediate (numerical) or
symbolic target addresses.
No change in code generation intended.
llvm-svn: 184721
A plain "sc" without argument is supposed to be treated like "sc 0"
by the assembler. This patch adds a corresponding alias.
Problem reported by Joerg Sonnenberger.
llvm-svn: 183687
The extended branch mnemonics are supposed to use an implied CR0
if there is no explicit condition register specified. This patch
adds extra variants of the mnemonics to this effect.
Problem reported by Joerg Sonnenberger.
llvm-svn: 183686
Now that there is no longer any distinction between symbolLo
and symbolHi operands in either printing, encoding, or parsing,
the operand types can be removed in favor of simply using
s16imm.
This completes the patch series to decouple lo/hi operand part
processing from the particular instruction whose operand it is.
No change in code generation expected from this patch.
llvm-svn: 182618
When targeting the Darwin assembler, we need to generate markers ha16() and
lo16() to designate the high and low parts of a (symbolic) immediate. This
is necessary not just for plain symbols, but also for certain symbolic
expression, typically along the lines of ha16(A - B). The latter doesn't
work when simply using VariantKind flags on the symbol reference.
This is why the current back-end uses hacks (explicitly called out as such
via multiple FIXMEs) in the symbolLo/symbolHi print methods.
This patch uses target-defined MCExpr codes to represent the Darwin
ha16/lo16 constructs, following along the lines of the equivalent solution
used by the ARM back end to handle their :upper16: / :lower16: markers.
This allows us to get rid of special handling both in the symbolLo/symbolHi
print method and in the common code MCExpr::print routine. Instead, the
ha16 / lo16 markers are printed simply in a custom print routine for the
target MCExpr types. (As a result, the symbolLo/symbolHi print methods
can now replaced by a single printS16ImmOperand routine that also handles
symbolic operands.)
The patch also provides a EvaluateAsRelocatableImpl routine to handle
ha16/lo16 constructs. This is not actually used at the moment by any
in-tree code, but is provided as it makes merging into David Fang's
out-of-tree Mach-O object writer simpler.
Since there is no longer any need to treat VK_PPC_GAS_HA16 and
VK_PPC_DARWIN_HA16 differently, they are merged into a single
VK_PPC_ADDR16_HA (and likewise for the _LO16 types).
llvm-svn: 182616
Using PatLeaf rather than ImmLeaf when defining immediate predicates
prevents simple patterns using those predicates from being recognized
for fast instruction selection. This patch replaces the immSExt16
PatLeaf predicate with two ImmLeaf predicates, imm32SExt16 and
imm64SExt16, allowing a few more patterns to be recognized (ADDI,
ADDIC, MULLI, ADDI8, and ADDIC8). Using the new predicates does not
help for LI, LI8, SUBFIC, and SUBFIC8 because these are rejected for
other reasons, but I see no reason to retain the PatLeaf predicate.
No functional change intended, and thus no test cases yet. This is
preliminary work for enabling fast-isel support for PowerPC. When
that support is ready, we'll be able to test this function.
llvm-svn: 182510
As the pairing of this instruction form with the bdnz/bdz branches is now
enforced by the verification pass, make it clear from the name that these
are used only for counter-based loops.
No functionality change intended.
llvm-svn: 182296
This patch implements the equivalent change to r182091/r182092
in the old-style code emitter. Instead of having two separate
16-bit immediate encoding routines depending on the instruction,
this patch introduces a single encoder that checks the machine
operand flags to decide whether the low or high half of a
symbol address is required.
Since now both encoders make no further distinction between
"symbolLo" and "symbolHi", the .td operand can now use a
single getS16ImmEncoding method.
Tested by running the old-style JIT tests on 32-bit Linux.
llvm-svn: 182097
This is the second part of the change to always return "true"
offset values from getPreIndexedAddressParts, tackling the
case of "memrix" type operands.
This is about instructions like LD/STD that only have a 14-bit
field to encode immediate offsets, which are implicitly extended
by two zero bits by the machine, so that in effect we can access
16-bit offsets as long as they are a multiple of 4.
The PowerPC back end currently handles such instructions by
carrying the 14-bit value (as it will get encoded into the
actual machine instructions) in the machine operand fields
for such instructions. This means that those values are
in fact not the true offset, but rather the offset divided
by 4 (and then truncated to an unsigned 14-bit value).
Like in the case fixed in r182012, this makes common code
operations on such offset values not work as expected.
Furthermore, there doesn't really appear to be any strong
reason why we should encode machine operands this way.
This patch therefore changes the encoding of "memrix" type
machine operands to simply contain the "true" offset value
as a signed immediate value, while enforcing the rules that
it must fit in a 16-bit signed value and must also be a
multiple of 4.
This change must be made simultaneously in all places that
access machine operands of this type. However, just about
all those changes make the code simpler; in many cases we
can now just share the same code for memri and memrix
operands.
llvm-svn: 182032
The old PPCCTRLoops pass, like the Hexagon pass version from which it was
derived, could only handle some simple loops in canonical form. We cannot
directly adapt the new Hexagon hardware loops pass, however, because the
Hexagon pass contains a fundamental assumption that non-constant-trip-count
loops will contain a guard, and this is not always true (the result being that
incorrect negative counts can be generated). With this commit, we replace the
pass with a late IR-level pass which makes use of SE to calculate the
backedge-taken counts and safely generate the loop-count expressions (including
any necessary max() parts). This IR level pass inserts custom intrinsics that
are lowered into the desired decrement-and-branch instructions.
The most fragile part of this new implementation is that interfering uses of
the counter register must be detected on the IR level (and, on PPC, this also
includes any indirect branches in addition to function calls). Also, to make
all of this work, we need a variant of the mtctr instruction that is marked
as having side effects. Without this, machine-code level CSE, DCE, etc.
illegally transform the resulting code. Hopefully, this can be improved
in the future.
This new pass is smaller than the original (and much smaller than the new
Hexagon hardware loops pass), and can handle many additional cases correctly.
In addition, the preheader-creation code has been copied from LoopSimplify, and
after we decide on where it belongs, this code will be refactored so that it
can be explicitly shared (making this implementation even smaller).
The new test-case files ctrloop-{le,lt,ne}.ll have been adapted from tests for
the new Hexagon pass. There are a few classes of loops that this pass does not
transform (noted by FIXMEs in the files), but these deficiencies can be
addressed within the SE infrastructure (thus helping many other passes as well).
llvm-svn: 181927
This patch adds a couple of Book II instructions (isync, icbi) to the
PowerPC assembler parser. These are needed when bootstrapping clang
with the integrated assembler forced on, because they are used in
inline asm statements in the code base.
The test case adds the full list of Book II storage control instructions,
including associated extended mnemonics. Again, those that are not yet
supported as marked as FIXME.
llvm-svn: 181052
This patch adds infrastructure to support extended mnemonics in the
PowerPC assembler parser. It adds support specifically for those
extended mnemonics that LLVM will itself generate.
The test case lists *all* extended mnemonics according to the
PowerPC ISA v2.06 Book I, but marks those not yet supported
as FIXME.
llvm-svn: 181051
This adds assembler parser support to the PowerPC back end.
The parser will run for any powerpc-*-* and powerpc64-*-* triples,
but was tested only on 64-bit Linux. The supported syntax is
intended to be compatible with the GNU assembler.
The parser does not yet support all PowerPC instructions, but
it does support anything that is generated by LLVM itself.
There is no support for testing restricted instruction sets yet,
i.e. the parser will always accept any instructions it knows,
no matter what feature flags are given.
Instruction operands will be checked for validity and errors
generated. (Error handling in general could still be improved.)
The patch adds a number of test cases to verify instruction
and operand encodings. The tests currently cover all instructions
from the following PowerPC ISA v2.06 Book I facilities:
Branch, Fixed-point, Floating-Point, and Vector.
Note that a number of these instructions are not yet supported
by the back end; they are marked with FIXME.
A number of follow-on check-ins will add extra features. When
they are all included, LLVM passes all tests (including bootstrap)
when using clang -cc1as as the system assembler.
llvm-svn: 181050
Joerg Sonnenberger