When there is no .debug_addr section for some reason,
llvm-dwarfdump would print the bogus empty section name when dumping ranges
in .debug_info:
DW_AT_ranges [DW_FORM_rnglistx] (indexed (0x0) rangelist = 0x00000004
[0x0000000000000000, 0x0000000000000001) ""
[0x0000000000000000, 0x0000000000000002) "")
That happens because of the code which uses 0 (zero) as a section index as a default value.
The code should use -1ULL instead because technically 0 is a valid zero section index
in ELF and -1ULL is a special constant used that means "no section available".
This is mostly a fix for the overall correctness/safety of the code,
but a test case is provided too.
Differential revision: https://reviews.llvm.org/D55113
llvm-svn: 348115
Currently, variadic operands on an MCInst are assumed to be uses,
because they come after the defs. However, this is not always the case,
for example the Arm/Thumb LDM instructions write to a variable number of
registers.
This adds a property of instruction definitions which can be used to
mark variadic operands as defs. This only affects MCInst, because
MachineInstruction already tracks use/def per operand in each instance
of the instruction, so can already represent this.
This property can then be checked in MCInstrDesc, allowing us to remove
some special cases in ARMAsmParser::isITBlockTerminator.
Differential revision: https://reviews.llvm.org/D54853
llvm-svn: 348114
In the Arm assembly parser, we first match an instruction, then call
processInstruction to possibly change it to a different encoding, to
match rules in the architecture manual which can't be expressed by the
table-generated matcher.
This adds debug printing so that this process is visible when using the
-debug option.
To support this, I've added a new overload of MCInst::dump_pretty which
takes the opcode name as a StringRef, since we don't have an InstPrinter
instance in the assembly parser. Instead, we can get the same
information directly from the MCInstrInfo.
Differential revision: https://reviews.llvm.org/D54852
llvm-svn: 348113
This change enables conservative assembly instrumentation in KMSAN builds
by default.
It's still possible to disable it with -msan-handle-asm-conservative=0
if something breaks. It's now impossible to enable conservative
instrumentation for userspace builds, but it's not used anyway.
llvm-svn: 348112
Summary:
There are 4 instructions which have Inconsistent ImmMustBeMultipleOf in the
function PPCInstrInfo::instrHasImmForm, they are LFS, LFD, STFS, STFD.
These four instructions should set the ImmMustBeMultipleOf to 1 instead of 4.
Reviewed By: steven.zhang
Differential Revision: https://reviews.llvm.org/D54738
llvm-svn: 348109
In theory, we should let the PPC target to determine how to lower the TOC Entry for globals.
And the PPCTargetLowering requires this query to do some optimization for TOC_Entry.
Differential Revision: https://reviews.llvm.org/D54925
llvm-svn: 348108
If the shift amount is known, we can determine the known bits of the
output based on the known bits of two inputs.
This is essentially the same functionality as implemented in D54869,
but for ValueTracking rather than InstCombine SimplifyDemandedBits.
Differential Revision: https://reviews.llvm.org/D55140
llvm-svn: 348091
This makes the SDAG behavior consistent with the way we do this in IR.
It's possible that we were getting the wrong answer before. For example,
'xor undef, undef --> 0' but 'xor undef, C' --> undef.
But the most practical improvement is likely as shown in the tests here -
for FP, we were overconstraining undef lanes to NaN, and that can prevent
vector simplifications/narrowing (see D51553).
llvm-svn: 348090
This change prevents the crash noted in the post-commit comments
for rL347478 :
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181119/605166.html
We can't guarantee that an oversized shift amount is folded away,
so we have to check for it.
Note that I committed an incomplete fix for that crash with:
rL347502
But as discussed here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181126/605679.html
...we have to try harder.
So I'm not sure how to expose the bug now (and apparently no fuzzers have found
a way yet either).
On the plus side, we have discovered that we're missing real optimizations by
not simplifying nodes sooner, so the earlier fix still has value, and there's
likely more value in extending that so we can simplify more opcodes and simplify
when doing RAUW and/or putting nodes on the combiner worklist.
Differential Revision: https://reviews.llvm.org/D54954
llvm-svn: 348089
We were duplicating code around the existing isImpliedCondition() that
checks for a predecessor block/dominating condition, so make that a
wrapper call.
llvm-svn: 348088
Previously this code generated its own extracts and build_vector. But we can use a simpler concat_vectors or scalar_to_vector operation and let type legalization do additional legalization of those operations.
llvm-svn: 348087
The generic legalizer will fall back to a stack spill that uses a truncating store. That store will get expanded into a shuffle and non-truncating store on pre-avx512 targets. Once that happens the stack store/load pair will be combined away leaving behind the shuffle and bitcasts. On avx512 targets the truncating store is legal so doesn't get folded away.
By custom legalizing it we can avoid this churn and maybe produce better code.
llvm-svn: 348085
If we know that we'll definitely save LR to a register, there's no reason to
pre-check whether or not a stack instruction is unsafe to fix up.
This makes it so that we check for that condition before mapping instructions.
This allows us to outline more, since we don't pessimise as many instructions.
Also update some tests, since we outline more.
llvm-svn: 348081
Summary: With sse4.1 we use two zero_extend_vector_inreg and a pshufd to expand the v16i8 input into two v8i16 vectors for the multiply. That's 3 shuffles to extend one operand. The other operand is usually constant as this is mostly used by division by constant optimization. Pre sse4.1 we use a punpckhbw and a punpcklbw with a zero vector. That's two shuffles and an xor and a copy due to tied register constraints. That seems maybe better than the 3 shuffles. With AVX we avoid the copy so that's obviously better.
Reviewers: spatel, RKSimon
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D55138
llvm-svn: 348079
The identity ~(x ^ y) == (~x ^ y) == (x ^ ~y) allows XNOR (XOR/NOT) to turn into NOT/XOR. Handling this case with its own split means we can make the NOT remain in the scalar unit. Previously, we split 64-bit XNOR into two 32-bit XNOR, then lowered. Now, we get three instructions (s_not, v_xor, v_xor) rather than four in the case where either of the sources is a scalar 64-bit.
Add test cases to xnor.ll to attempt XNOR Vx, Sy and XNOR Sx, Vy. Also adding test that uses the opposite identity such that (~x ^ y) on the scalar unit (or vector for gfx906) can generate XNOR. This already worked, but I didn't see a test for it.
Differential: https://reviews.llvm.org/D55071
llvm-svn: 348075
D52935 introduced the ability for SimplifyDemandedBits to call SimplifyDemandedVectorElts through BITCASTs if the demanded bit mask entirely covered the sub element.
This patch relaxes this to demanding an element if we need any bit from it.
Differential Revision: https://reviews.llvm.org/D54761
llvm-svn: 348073
Extend ssub.sat(X, C) -> sadd.sat(X, -C) canonicalization to also
support non-splat vector constants. This is done by generalizing
the implementation of the isNotMinSignedValue() helper to return
true for constants that are non-splat, but don't contain any
signed min elements.
Differential Revision: https://reviews.llvm.org/D55011
llvm-svn: 348072
Summary:
Follow up to D54270, which allowed importing of var args functions
unless they called va_start. As pointed out in the post-commit comments
on that patch, the inliner can handle functions that call va_start in
certain situations as well. Go ahead and enable importing of all var
args functions. Measurements on a large binary show that this increases
imports and binary size by an insignificant amount.
Reviewers: davidxl
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D54607
llvm-svn: 348068
As noted by Eli Friedman <https://reviews.llvm.org/D52977?id=168629#1315291>,
the RV64I shift patterns for SLLW/SRLW/SRAW make some incorrect assumptions.
SRAW assumed that (sext_inreg foo, i32) could only be produced when
sign-extended an i32. However, it can be produced by input such as:
define i64 @tricky_ashr(i64 %a, i64 %b) {
%1 = shl i64 %a, 32
%2 = ashr i64 %1, 32
%3 = ashr i64 %2, %b
ret i64 %3
}
It's important not to select sraw in the above case, because sraw only uses
bits lower 5 bits from the shift, while a shift of 32-63 would be valid.
Similarly, the patterns for srlw assumed (and foo, 0xffffffff) would only be
produced when zero-extending a value that was originally i32 in LLVM IR. This
is obviously incorrect.
This patch removes the SLLW/SRLW/SRAW shift patterns for the time being and
adds test cases that would demonstrate a miscompile if the incorrect patterns
were re-added.
llvm-svn: 348067
identify_magic does not need the file to be null terminated. Passing
true here causes the file reading code to decide not to use mmap in
some rare cases (which happen to be true 100% of the time in PDB files)
which can lead to very large files failing to load. Since it was
probably just an accident that we were passing true here (since it is
the default function parameter), this should be strictly an improvement.
llvm-svn: 348059
Summary:
Moving SMRD to VMEM in SIFixSGPRCopies is rather bad for performance if
the load is really uniform. So select the scalar load intrinsics directly
to either VMEM or SMRD buffer loads based on divergence analysis.
If an offset happens to end up in a VGPR -- either because a floating
point calculation was involved, or due to other remaining deficiencies
in SIFixSGPRCopies -- we use v_readfirstlane.
There is some unrelated churn in tests since we now select MUBUF offsets
in a unified way with non-scalar buffer loads.
Change-Id: I170e6816323beb1348677b358c9d380865cd1a19
Reviewers: arsenm, alex-t, rampitec, tpr
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, t-tye, llvm-commits
Differential Revision: https://reviews.llvm.org/D53283
llvm-svn: 348050
Summary:
The VirtReg2Value mapping is crucial for getting consistently
reliable divergence information into the SelectionDAG. This
patch fixes a bunch of issues that lead to incorrect divergence
info and introduces tight assertions to ensure we don't regress:
1. VirtReg2Value is generated lazily; there were some cases where
a lookup was performed before all relevant virtual registers were
created, leading to an out-of-sync mapping. Those cases were:
- Complex code to lower formal arguments that generated CopyFromReg
nodes from live-in registers (fixed by never querying the mapping
for live-in registers).
- Code that generates CopyToReg for formal arguments that are used
outside the entry basic block (fixed by never querying the
mapping for Register nodes, which don't need the divergence info
anyway).
2. For complex values that are lowered to a sequence of registers,
all registers must be reflected in the VirtReg2Value mapping.
I am not adding any new tests, since I'm not actually aware of any
bugs that these problems are causing with trunk as-is. However,
I recently added a test case (in r346423) which fails when D53283 is
applied without this change. Also, the new assertions should provide
most of the effective test coverage.
There is one test change in sdwa-peephole.ll. The underlying issue
is that since the divergence info is now correct, the DAGISel will
select V_OR_B32 directly instead of S_OR_B32. This leads to an extra
COPY which affects the behavior of MachineLICM in a way that ends up
with the S_MOV_B32 with the constant in a different basic block than
the V_OR_B32, which is presumably what defeats the peephole.
Reviewers: alex-t, arsenm, rampitec
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, llvm-commits
Differential Revision: https://reviews.llvm.org/D54340
llvm-svn: 348049
Summary:
This is patch #3 of the new DivergenceAnalysis
<https://lists.llvm.org/pipermail/llvm-dev/2018-May/123606.html>
The GPUDivergenceAnalysis is intended to eventually supersede the existing
LegacyDivergenceAnalysis. The existing LegacyDivergenceAnalysis produces
incorrect results on unstructured Control-Flow Graphs:
<https://bugs.llvm.org/show_bug.cgi?id=37185>
This patch adds the option -use-gpu-divergence-analysis to the
LegacyDivergenceAnalysis to turn it into a transparent wrapper for the
GPUDivergenceAnalysis.
Reviewers: nhaehnle
Reviewed By: nhaehnle
Subscribers: jholewinski, jvesely, jfb, llvm-commits, alex-t, sameerds, arsenm, nhaehnle
Differential Revision: https://reviews.llvm.org/D53493
llvm-svn: 348048
Instead of treating the outlined functions for these as distinct frames, they
should be combined into one case. Neither allows for stack fixups, and both
generate the same frame. Thus, they ought to be considered one case.
This makes the code far easier to understand, for one thing. It also offers
some small code size improvements. It's fairly rare to see a class of outlined
functions that doesn't fall entirely into one variant (on CTMark anyway). It
does happen from time to time though.
This mostly offers some serious simplification.
Also update the test to show the added functionality.
llvm-svn: 348036
All that you can legitimately do with the CFI for a nounwind function
is get a backtrace, and adjusting the SCS register is not (currently)
required for this purpose.
Differential Revision: https://reviews.llvm.org/D54988
llvm-svn: 348035
Summary:
When mem2reg inserts phi nodes in blocks with unreachable predecessors,
it adds undef operands for those incoming edges. When there are
multiple such predecessors, the order is currently based on the address
of the BasicBlocks. This change fixes that by using the BBNumbers in
the sort/search predicates, as is done elsewhere in mem2reg to ensure
determinism.
Also adds a testcase with a bunch of unreachable preds, which
(nodeterministically) fails without the fix.
Reviewers: majnemer
Reviewed By: majnemer
Subscribers: mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D55077
llvm-svn: 348024
Update IR verifier to check the constraint that DIFile source is present on all
files or no files.
Differential Revision: https://reviews.llvm.org/D54953
llvm-svn: 348022
This reduces the number of shuffle operations that need to be done. The splitting strategy requires the shuffle unit for the extraction and the extension. With the unpack strategy the unpacks accomplish a splitting and extending in one operation.
llvm-svn: 348019
This does require a constant pool load instead of loading an immediate into a gpr, moving to a k register and masking. But its less instructions and more consistent with previous ISAs. It probably opens up more combine opportunities as one of the test cases demonstrates.
llvm-svn: 348018
This patch adds BPF Debug Format (BTF) as a standalone
LLVM debuginfo. The BTF related sections are directly
generated from IR. The BTF debuginfo is generated
only when the compilation target is BPF.
What is BTF?
============
First, the BPF is a linux kernel virtual machine
and widely used for tracing, networking and security.
https://www.kernel.org/doc/Documentation/networking/filter.txthttps://cilium.readthedocs.io/en/v1.2/bpf/
BTF is the debug info format for BPF, introduced in the below
linux patch
69b693f0ae (diff-06fb1c8825f653d7e539058b72c83332)
in the patch set mentioned in the below lwn article.
https://lwn.net/Articles/752047/
The BTF format is specified in the above github commit.
In summary, its layout looks like
struct btf_header
type subsection (a list of types)
string subsection (a list of strings)
With such information, the kernel and the user space is able to
pretty print a particular bpf map key/value. One possible example below:
Withtout BTF:
key: [ 0x01, 0x01, 0x00, 0x00 ]
With BTF:
key: struct t { a : 1; b : 1; c : 0}
where struct is defined as
struct t { char a; char b; short c; };
How BTF is generated?
=====================
Currently, the BTF is generated through pahole.
https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=68645f7facc2eb69d0aeb2dd7d2f0cac0feb4d69
and available in pahole v1.12
https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=4a21c5c8db0fcd2a279d067ecfb731596de822d4
Basically, the bpf program needs to be compiled with -g with
dwarf sections generated. The pahole is enhanced such that
a .BTF section can be generated based on dwarf. This format
of the .BTF section matches the format expected by
the kernel, so a bpf loader can just take the .BTF section
and load it into the kernel.
8a138aed4a
The .BTF section layout is also specified in this patch:
with file include/llvm/BinaryFormat/BTF.h.
What use cases this patch tries to address?
===========================================
Currently, only the bpf instruction stream is required to
pass to the kernel. The kernel verifies it, jits it if configured
to do so, attaches it to a particular kernel attachment point,
and later executes when a particular event happens.
This patch tries to expand BTF to support two more use cases below:
(1). BPF supports subroutine calls.
During performance analysis, it would be good to
differentiate which call is hot instead of just
providing a virtual address. This would require to
pass a unique identifier for each subroutine to
the kernel, the subroutine name is a natual choice.
(2). If a particular jitted instruction is hot, we want
user to know which source line this jitted instruction
belongs to. This would require the source information
is available to various profiling tools.
Note that in a single ELF file,
. there may be multiple loadable bpf programs,
. for a particular to-be-loaded bpf instruction stream,
its instructions may come from multiple PROGBITS sections,
the bpf loader needs to merge them together to a single
consecutive insn stream before loading to the kernel.
For example:
section .text: subroutines funcFoo
section _progA: calling funcFoo
section _progB: calling funcFoo
The bpf loader could construct two loadable bpf instruction
streams and load them into the kernel:
. _progA funcFoo
. _progB funcFoo
So per ELF section function offset and instruction offset
will need to be adjusted before passing to the kernel, and
the kernel essentially expect only one code section regardless
of how many in the ELF file.
What do we propose and Why?
===========================
To support the above two use cases, we propose to
add an additional section, .BTF.ext, to the ELF file
which is the input of the bpf loader. A different section
is preferred since loader may need to manipulate it before
loading part of its data to the kernel.
The .BTF.ext section has a similar header to the .BTF section
and it contains two subsections for func_info and line_info.
. the func_info maps the func insn byte offset to a func
type in the .BTF type subsection.
. the line_info maps the insn byte offset to a line info.
. both func_info and line_info subsections are organized
by ELF PROGBITS AX sections.
pahole is not a good place to implement .BTF.ext as
pahole is mostly for structure hole information and more
importantly, we want to pass the actual code to the kernel.
. bpf program typically is small so storage overhead
should be small.
. in bpf land, it is totally possible that
an application loads the bpf program into the
kernel and then that application quits, so
holding debug info by the user space application
is not practical as you may not even know who
loads this bpf program.
. having source codes directly kept by kernel
would ease deployment since the original source
code does not need ship on every hosts and
kernel-devel package does not need to be
deployed even if kernel headers are used.
LLVM is a good place to implement.
. The only reliable time to get the source code is
during compilation time. This will result in both more
accurate information and easier deployment as
stated in the above.
. Another consideration is for JIT. The project like bcc
(https://github.com/iovisor/bcc)
use MCJIT to compile a C program into bpf insns and
load them to the kernel. The llvm generated BTF sections
will be readily available for such cases as well.
Design and implementation of emiting .BTF/.BTF.ext sections
===========================================================
The BTF debuginfo format is defined. Both .BTF and .BTF.ext
sections are generated directly from IR when both
"-target bpf" and "-g" are specified. Note that
dwarf sections are still generated as dwarf is used
by user space tools like llvm-objdump etc. for BPF target.
This patch also contains tests to verify generated
.BTF and .BTF.ext sections for all supported types, func_info
and line_info subsections. The patch is also tested
against linux kernel bpf sample tests and selftests.
Signed-off-by: Yonghong Song <yhs@fb.com>
Differential Revision: https://reviews.llvm.org/D53736
llvm-svn: 347999
Summary:
If a given liveness arg of STATEPOINT is at a fixed frame index
(e.g. a function argument passed on stack), prefer to use this
fixed location even the address is also in a register. If we use
the register it will generate a spill, which is not necessary
since the fixed frame index can be directly recorded in the stack
map.
Patch by Cherry Zhang <cherryyz@google.com>.
Reviewers: thanm, niravd, reames
Reviewed By: reames
Subscribers: cherryyz, reames, anna, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D53889
llvm-svn: 347998
Summary:
An additional fix for PR39774. Need to update the references for the
RedcutionRoot instruction when it is replaced during the vectorization
phase to avoid compiler crash on reduction vectorization.
Reviewers: RKSimon, spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D55017
llvm-svn: 347997
Introduces DPP pseudo instructions and the pass that combines DPP mov with subsequent uses.
Differential revision: https://reviews.llvm.org/D53762
llvm-svn: 347993
Summary:
This simplifies writing predicates for pattern fragments that are
automatically re-associated or commuted.
For example, a followup patch adds patterns for fragments of the form
(add (shl $x, $y), $z) to the AMDGPU backend. Such patterns are
automatically commuted to (add $z, (shl $x, $y)), which makes it basically
impossible to refer to $x, $y, and $z generically in the PredicateCode.
With this change, the PredicateCode can refer to $x, $y, and $z simply
as `Operands[i]`.
Test confirmed that there are no changes to any of the generated files
when building all (non-experimental) targets.
Change-Id: I61c00ace7eed42c1d4edc4c5351174b56b77a79c
Reviewers: arsenm, rampitec, RKSimon, craig.topper, hfinkel, uweigand
Subscribers: wdng, tpr, llvm-commits
Differential Revision: https://reviews.llvm.org/D51994
llvm-svn: 347992
This patch adds CSR instructions aliases for the cases where the instruction
takes an immediate operand but the alias doesn't have the i suffix. This is
necessary for gas/gcc compatibility.
gas doesn't do a similar conversion for fsflags or fsrm, so this should be
complete.
Differential Revision: https://reviews.llvm.org/D55008
Patch by Luís Marques.
llvm-svn: 347991
Adding a new reduction pattern match for vectorizing code similar
to TSVC s3111:
for (int i = 0; i < N; i++)
if (a[i] > b)
sum += a[i];
This patch adds support for fadd, fsub and fmull, as well as multiple
branches and different (but compatible) instructions (ex. add+sub) in
different branches.
The difference from the previous patch(https://reviews.llvm.org/D49168)
is as follows:
- Added check of fast-math property of fp-instruction to the
previous patch
- Fix/add some pattern for if-reduction.ll
Differential Revision: https://reviews.llvm.org/D54464
Patch by Takahiro Miyoshi <takahiro.miyoshi@linaro.org>
and Masakazu Ueno <masakazu.ueno@linaro.org>
llvm-svn: 347989
This patch adds support for UNIMP in both 32- and 16-bit forms. The 32-bit
form can be seen as a variant of the ECALL/EBREAK/etc. family of instructions.
The 16-bit form is just all zeroes, which isn't a valid RISC-V instruction,
but still follows the 16-bit instruction form (i.e. bits 0-1 != 11).
Until recently unimp was undocumented and supported just by binutils, which
printed unimp for either the 16 or 32-bit form. Both forms are now documented
<https://github.com/riscv/riscv-asm-manual/pull/20> and binutils now supports
c.unimp <https://sourceware.org/ml/binutils-cvs/2018-11/msg00179.html>.
Differential Revision: https://reviews.llvm.org/D54316
Patch by Luís Marques.
llvm-svn: 347988
For targets where i32 is not a legal type (e.g. 64-bit RISC-V),
LegalizeIntegerTypes must promote the result of ISD::FLT_ROUNDS_.
Differential Revision: https://reviews.llvm.org/D53820
llvm-svn: 347986
For targets where i32 is not a legal type (e.g. 64-bit RISC-V),
LegalizeIntegerTypes must promote the operands of ISD::PREFETCH.
Differential Revision: https://reviews.llvm.org/D53281
llvm-svn: 347980
Terminator folding transform lacks MemorySSA update for memory Phis,
while they exist within MemorySSA analysis. They need exactly the same
type of updates as regular Phis. Failing to update them properly ends up
with inconsistent MemorySSA and manifests in various assertion failures.
This patch adds Memory Phi updates to this transform.
Thanks to @jonpa for finding this!
Differential Revision: https://reviews.llvm.org/D55050
Reviewed By: asbirlea
llvm-svn: 347979
