The help text and documentation for the --discard-all option failed to
mention that the option also causes the removal of debug sections. This
change fixes both for both llvm-objcopy and llvm-strip.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D97662
The check for whether an extended symbol index table was required
dropped the first SHN_LORESERVE sections from the sections array before
checking whether the remaining sections had symbols. Unfortunately, the
null section header is not present in this list, so the check was
skipping the first section that might be important. If that section
contained a symbol, and no subsequent ones did, the .symtab_shndx
section would not be emitted, leading to a corrupt object.
Also consolidate and expand test coverage in the area to cover this bug
and other aspects of the SYMTAB_SHNDX section.
Reviewed by: alexshap, MaskRay
Differential Revision: https://reviews.llvm.org/D97661
This removes the unit test from a968e7b82eac as it reportedly causes
some link problems. It can be reinstated once the issues are understood
and sorted out.
This patch enables the case where we do not completely eliminate offset.
Supposedly in this case we reduce live range overlap that never harms, but
since there are doubts this is true, this goes as a separate change.
Differential Revision: https://reviews.llvm.org/D96399
Reviewed By: reames
Additionally do some test tidy-ups and improve coverage of symbol
section indexes where the logical section index >= SHN_LORESERVE.
The symbol and section names in the many-section input object were
mostly shared. This patch changes them to be distinct, enabling
different operations such as --add-symbol, to be more targeted, when
using the object. It also makes the test less confusing and removes some
oddness in the symbol table order, presumably caused by the duplicate
names.
The input object was built from assembly that was of the form:
.section s1
sym1:
.section s2
sym2:
...
with a total of 65536 such occurrences. llvm-objcopy was then used to
remove the empty .text section automatically generated by MC, and
incidentally to move .strtab to the end of the object. This ensured that
the section/symbol indexes matched their name (i.e. section index 1 was
s1, section index 2 was s2 etc, and sym1 was in s1, sym2 in s2 etc).
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D97660
This patch addresses a compiler crash resulting from passing a
fixed-length type to one that expects scalable vector types. An
assertion was added to prevent this regressing in the future.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D97868
This patch fixes up one case where the fixed-length-vector VL was
dropped (falling back to VLMAX) when inserting vector elements, as the
code would lower via ISD::INSERT_VECTOR_ELT (at index 0) which loses the
fixed-length vector information.
To this end, a custom node, VMV_S_XF_VL, was introduced to carry the VL
operand through to the final instruction. This node wraps the RVV
vmv.s.x and vmv.s.f instructions, which were being selected by
insert_vector_elt anyway.
There should be no observable difference in scalable-vector codegen.
There is still one outstanding drop from fixed-length VL to VLMAX, when
an i64 element is inserted into a vector on RV32; the splat (which is
custom legalized) has no notion of the original fixed-length vector
type.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D97842
This adds some simple known bits handling for the three CSINC/NEG/INV
instructions. From the operands known bits we can compute the common
bits of the first operand and incremented/negated/inverted second
operand. The first, especially CSINC ZR, ZR, comes up fair amount in the
tests. The others are more rare so a unit test for them is added.
Differential Revision: https://reviews.llvm.org/D97788
While optimizing the memory instruction, we sometimes need to add
offset to the value of `IV`. We could avoid doing so if the `IV.next` is
already defined at the point of interest. In this case, we may get two
possible advantages from this:
- If the `IV` step happens to match with the offset, we don't need to add
the offset at all;
- We reduce overlap of live ranges of `IV` and `IV.next`. They may stop overlapping
and it will lead to better register allocation. Even if the overlap will preserve,
we are not introducing a new overlap, so it should be a neutral transform (Disabled
this patch, will come with follow-up).
Currently I've only added support for IVs that get decremented using `usub`
intrinsic. We could also support `AddInstr`, however there is some weird
interaction with some other transform that may lead to infinite compilation
in this case (seems like same transform is done and undone over and over).
I need to investigate why it happens, but generally we could do that too.
The first part only handles case where this reuse fully elimiates the offset.
Differential Revision: https://reviews.llvm.org/D96399
Reviewed By: reames
Same dangling probes are redundant since they all have the same semantic that is to rely on the counts inference tool to get reasonable count for the same original block. Therefore, there's no need to keep multiple copies of them. I've seen jump threading created tons of redundant dangling probes that slowed down the compiler dramatically. Other optimization passes can also result in redundant probes though without an observed impact so far.
This change removes block-wise redundant dangling probes specifically introduced by jump threading. To support removing redundant dangling probes caused by all other passes, a final function-wise deduplication is also added.
An 18% size win of the .pseudo_probe section was seen for SPEC2017. No performance difference was observed.
Differential Revision: https://reviews.llvm.org/D97482
This change fixes a couple places where the pseudo probe intrinsic blocks optimizations because they are not naturally removable. To unblock those optimizations, the blocking pseudo probes are moved out of the original blocks and tagged dangling, instead of allowing pseudo probes to be literally removed. The reason is that when the original block is removed, we won't be able to sample it. Instead of assigning it a zero weight, moving all its pseudo probes into another block and marking them dangling should allow the counts inference a chance to assign them a more reasonable weight. We have not seen counts quality degradation from our experiments.
The optimizations being unblocked are:
1. Removing conditional probes for if-converted branches. Conditional probes are tagged dangling when their homing branch arms are folded so that they will not be over-counted.
2. Unblocking jump threading from removing empty blocks. Pseudo probe prevents jump threading from removing logically empty blocks that only has one unconditional jump instructions.
3. Unblocking SimplifyCFG and MIR tail duplicate to thread empty blocks and blocks with redundant branch checks.
Since dangling probes are logically deleted, they should not consume any samples in LTO postLink. This can be achieved by setting their distribution factors to zero when dangled.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D97481
Dangling probes are the probes associated to an empty block. This usually happens when all real instructions are optimized away from the block. There is a problem with dangling probes during the offline counts processing. The way the sample profiler works is that samples collected on the first physical instruction following a probe will be counted towards the probe. This logically equals to treating the instruction next to a probe as if it is from the same block of the probe. In the dangling probe case, the real instruction following a dangling probe actually starts a new block, and samples collected on the new block may cause issues when counted towards the empty block.
To mitigate this issue, we first try to move around a dangling probe inside its owning block. If there are still native instructions preceding the probe in the same block, we can then use them as a place holder to collect samples for the probe. A pass is added to walk each block backwards looking for probes not followed by any real instruction and moving them before the first real instruction. This is done right before the object emission.
If we are unlucky to find such in-block preceding instructions for a probe, the solution we are taking is to tag such probe as dangling so that the samples reported for them will not be trusted by the compiler. We leave it up to the counts inference algorithm to get such probes a reasonable count. The number `UINT64_MAX` is used to mark sample count as collected for a dangling probe.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D95962
We don't need a bool and an enum to express the three options we
currently have. This makes the interface nicer and much easier to
use optional dependencies. Also avoids mistakes where the bool is
false and enum ignored.
This is an attempt to improve handling of partial overlaps in case of unaligned begin\end.
Existing implementation just bails out if it encounters such cases. Even when it doesn't I believe existing code checking alignment constraints is not quite correct. It tries to ensure alignment of the "later" start/end offset while should be preserving relative alignment between earlier and later start/end.
The idea behind the change is simple. When start/end is not aligned as we wish instead of bailing out let's adjust it as necessary to get desired alignment.
I'll update with performance results as measured by the test-suite...it's still running...
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D93530
statepoint intrinsic can be used in invoke context,
so it should be handled in visitCallBase to cover both call and invoke.
Reviewers: reames, dantrushin
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D97833
This patch is an update to LangRef by describing lifetime intrinsics' behavior
by following the description of MIR's LIFETIME_START/LIFETIME_END markers
at StackColoring.cpp (eb44682d67/llvm/lib/CodeGen/StackColoring.cpp (L163)) and the discussion in llvm-dev.
In order to explicitly define the meaning of an object lifetime, I added 'Object Lifetime' subsection.
Reviewed By: nlopes
Differential Revision: https://reviews.llvm.org/D94002
IR symbol table does not parse inline asm. A symbol only referenced by inline
asm is not in the IR symbol table, so LTO does not know that the definition (in
another translation unit) is referenced and may internalize it, even if that
definition has `__attribute__((used))` (which lowers to `llvm.compiler.used` on
ELF targets since D97446).
```
// cabac.c
__attribute__((used)) const uint8_t ff_h264_cabac_tables[...] = {...};
// h264_cabac.c
asm("lea ff_h264_cabac_tables(%rip), %0" : ...);
```
`__attribute__((used))` is the recommended way to tell the compiler there may
be inline asm references, so the usage is perfectly fine. This patch
conservatively sets the `FB_used` bit on `llvm.compiler.used` symbols to work
around the IR symbol table limitation. Note: before D97446, Clang never emitted
symbols in the `llvm.compiler.used` list, so this change does not punish any
Clang emitted global object.
Without the patch, `ff_h264_cabac_tables` may be assigned to a non-external
partition and get internalized. Then we will get a linker error because the
`cabac.c` definition is not exposed.
Differential Revision: https://reviews.llvm.org/D97755
See pr46990(https://bugs.llvm.org/show_bug.cgi?id=46990). LICM should not sink store instructions to loop exit blocks which cross coro.suspend intrinsics. This breaks semantic of coro.suspend intrinsic which return to caller directly. Also this leads to use-after-free if the coroutine is freed before control returns to the caller in multithread environment.
This patch disable promotion by check whether loop contains coro.suspend intrinsics.
This is a resubmit of D86190.
Disabling LICM for loops with coroutine suspension is a better option not only for correctness purpose but also for performance purpose.
In most cases LICM sinks memory operations. In the case of coroutine, sinking memory operation out of the loop does not improve performance since coroutien needs to get data from the frame anyway. In fact LICM would hurt coroutine performance since it adds more entries to the frame.
Differential Revision: https://reviews.llvm.org/D96928
The compiler needs to mark register $x0 as live in for the following case.
$x1 = ADDXri $sp, 16, 0
BL @spam, csr_darwin_aarch64_aapcs, implicit-def dead $lr, implicit $sp, implicit $x0, implicit killed $x1, implicit-def $sp, implicit-def dead $x0
Reviewed By: paquette
Differential Revision: https://reviews.llvm.org/D95267
As a preparation step for fast8 support, we need to update the tests
to pass in both modes. That requires generalizing the shadow width
and remove any hard coded references that assume it's always 2 bytes.
Reviewed By: stephan.yichao.zhao
Differential Revision: https://reviews.llvm.org/D97884
This is a mess, but this is hopefully no-functional-change.
The 'Prev' descriptor is only used for min/max recurrences
or when starting a match from a phi, so it should not be a
factor when propagating FMF for fmul/fadd.
The API is confusing (and should be reduced in subsequent steps)
because the "UnsafeAlgebraInst" appears to actually be a placeholder
for a recurrence that does NOT have FMF, but we still want to
treat it as reassociative.
Make sure we preserve info about passed arguments as implicit uses, to
make sure later passes still have access to this information.
This fixes a mis-compile where the machine-combiner would pick an
incorrect free register.
This reverts commit 900f076113302e26e1939541b546b0075e3e9721 and attempts an actual fix: All failing tests for llvm-jitlink use the `-noexec` flag. The inputs they operate on are not meant for execution on the host system. Looking e.g. at the MachO_test_harness_harnesss.s test, llvm-mc generates input machine code with "x86_64-apple-macosx10.9".
My previous attempt in bbdb4c8c9bcef0e8db751630accc04ad874f54e7 disabled the debug support plugin for Windows targets, but what we would actually want is to disable it on Windows HOSTS.
With the new patch here, I don't do exactly that, but instead follow the approach for the EH frame plugin and include the `-noexec` flag in the condition. It should have the desired effect when it comes to the test suite. It appears a little workaround'ish, but should work reliably for now. I will discuss the issue with Lang and see if we can do better. Thanks @thakis again for the temporary fix.
Probably should have done this before landing, but I forgot.
Basic idea is to avoid using the SCEV predicate when it doesn't buy us anything. Also happens to set us up for handling non-add recurrences in the future if desired.
LSR goes to some lengths to schedule IV increments such that %iv and %iv.next never need to overlap. This is fairly fundamental to LSRs cost model. LSR assumes that an addrec can be represented with a single register. If %iv and %iv.next have to overlap, then that assumption does not hold.
The bug - which this patch is fixing - is that LSR only does this scheduling for IVs which it inserts, but it's cost model assumes the same for existing IVs that it reuses. It will rewrite existing IV users such that the no-overlap property holds, but will not actually reschedule said IV increment.
As you can see from the relatively lack of test updates, this doesn't actually impact codegen much. The main reason for doing it is to make a follow up patch series which improves post-increment use and scheduling easier to follow.
Differential Revision: https://reviews.llvm.org/D97219
Even though the implementation in emitAtomicCmpSwapW() was correct, it made
Valgrind report an error. Instead of using a RISBG on CmpVal, an LL[CH]R can
be made on the OldVal, and the problem is avoided.
Review: Ulrich Weigand
Differential Revision: https://reviews.llvm.org/D97604
This is a NFC with respect to the generated code. But it fixes a crash
when using -debug, because of the position in the enum CALL_RVMARKER
nodes were treated as memops. That caused a crash when printing
CALL_RVMARKER nodes.
`__llvm_prf_vnodes` and `__llvm_prf_names` are used by runtime but not
referenced via relocation in the translation unit.
With `-z start-stop-gc` (LLD 13 (D96914); GNU ld 2.37 https://sourceware.org/bugzilla/show_bug.cgi?id=27451),
the linker does not let `__start_/__stop_` references retain their sections.
Place `__llvm_prf_vnodes` and `__llvm_prf_names` in `llvm.used` to make
them retained by the linker.
This patch changes most existing `UsedVars` cases to `CompilerUsedVars`
to reflect the ideal state - if the binary format properly supports
section based GC (dead stripping), `llvm.compiler.used` should be sufficient.
`__llvm_prf_vnodes` and `__llvm_prf_names` are switched to `UsedVars`
since we want them to be unconditionally retained by both compiler and linker.
Behaviors on COFF/Mach-O are not affected.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D97649
As a preparation step for fast8 support, we need to update the tests
to pass in both modes. That requires generalizing the shadow width
and remove any hard coded references that assume it's always 2 bytes.
Reviewed By: stephan.yichao.zhao
Differential Revision: https://reviews.llvm.org/D97723
Honor always_inline attribute when processing -amdgpu-inline-max-bb.
It was lost during the ports of the heuristic. There is no reason
to honor inline hint, but not always inline.
Differential Revision: https://reviews.llvm.org/D97790
Previously we errored out when disassembling illegal instructions and there would be no profile generated. In fact illegal instructions are not uncommon and we'd better skip them and print "unknown" instead of erroring out. This matches the behavior of llvm-objdump (see disassembleObject in llvm-objdump.cpp).
Reviewed By: wlei, wenlei
Differential Revision: https://reviews.llvm.org/D97776
