Arranging the language specific property section into readable groupings and adding a couple of notes about pass order, extensions, and the like.
For the record, suggestion for word smithing are welcomed. I'm happy to revise; I'm just trying to get *something* in place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245855 91177308-0d34-0410-b5e6-96231b3b80d8
This change just groups the suggestions by broad topic. I'm planning a couple of follow on changes to improve the readability of this document.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245854 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds support for dfsan on aarch64-linux with 42-bit VMA
(current default config for 64K pagesize kernels). The support is
enabled by defining the SANITIZER_AARCH64_VMA to 42 at build time
for both clang/llvm and compiler-rt. The default VMA is 39 bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245840 91177308-0d34-0410-b5e6-96231b3b80d8
The FP16_TO_FP node only uses the bottom 16 bits of its input, so the
following pattern can be optimised by removing the AND:
(FP16_TO_FP (AND op, 0xffff)) -> (FP16_TO_FP op)
This is a common pattern for ARM targets when functions have __fp16
arguments, as they are passed as floats (so that they get passed in the
correct registers), but then bitcast and truncated to ignore the top 16
bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245832 91177308-0d34-0410-b5e6-96231b3b80d8
TL-DR: SROA is followed by EarlyCSE which requires the DominatorTree.
There is no reason not to require it up-front for SROA.
Some history is necessary to understand why we ended-up here.
r123437 switched the second (Legacy)SROA in the optimizer pipeline to
use SSAUpdater in order to avoid recomputing the costly
DominanceFrontier. The purpose was to speed-up the compile-time.
Later r123609 removed the need for the DominanceFrontier in
(Legacy)SROA.
Right after, some cleanup was made in r123724 to remove any reference
to the DominanceFrontier. SROA existed in two flavors: SROA_SSAUp and
SROA_DT (the latter replacing SROA_DF).
The second argument of `createScalarReplAggregatesPass` was renamed
from `UseDomFrontier` to `UseDomTree`.
I believe this is were a mistake was made. The pipeline was not
updated and the call site was still:
PM->add(createScalarReplAggregatesPass(-1, false));
At that time, SROA was immediately followed in the pipeline by
EarlyCSE which required alread the DominatorTree. Not requiring
the DominatorTree in SROA didn't save anything, but unfortunately
it was lost at this point.
When the new SROA Pass was introduced in r163965, I believe the goal
was to have an exact replacement of the existing SROA, this bug
slipped through.
You can see currently:
$ echo "" | clang -x c++ -O3 -c - -mllvm -debug-pass=Structure
...
...
FunctionPass Manager
SROA
Dominator Tree Construction
Early CSE
After this patch:
$ echo "" | clang -x c++ -O3 -c - -mllvm -debug-pass=Structure
...
...
FunctionPass Manager
Dominator Tree Construction
SROA
Early CSE
This improves the compile time from 88s to 23s for PR17855.
https://llvm.org/bugs/show_bug.cgi?id=17855
And from 113s to 12s for PR16756
https://llvm.org/bugs/show_bug.cgi?id=16756
Reviewers: chandlerc
Differential Revision: http://reviews.llvm.org/D12267
From: Mehdi Amini <mehdi.amini@apple.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245820 91177308-0d34-0410-b5e6-96231b3b80d8
Minor generalization of D12125 - peek through any bitcast to the original vector that we're extracting from.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245814 91177308-0d34-0410-b5e6-96231b3b80d8
Not only do we not need to do anything to read correct values from the
object files, but the current logic actually wrongly applies twice the
section base address when there is no LoadedObjectInfo passed to the
DWARFContext creation (as the added test shows).
Simply do not apply any relocations on the mach-o debug info if there is
no load offset to apply.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245807 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds all the refactored tests in new files, the old
tests will be removed by a followup commit.
Thanks to D. Blaikie for all the feedback.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245803 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
WinEHPrepare is going to require that cleanuppad and catchpad produce values
of token type which are consumed by any cleanupret or catchret exiting the
pad. This change updates the signatures of those operators to require/enforce
that the type produced by the pads is token type and that the rets have an
appropriate argument.
The catchpad argument of a `CatchReturnInst` must be a `CatchPadInst` (and
similarly for `CleanupReturnInst`/`CleanupPadInst`). To accommodate that
restriction, this change adds a notion of an operator constraint to both
LLParser and BitcodeReader, allowing appropriate sentinels to be constructed
for forward references and appropriate error messages to be emitted for
illegal inputs.
Also add a verifier rule (noted in LangRef) that a catchpad with a catchpad
predecessor must have no other predecessors; this ensures that WinEHPrepare
will see the expected linear relationship between sibling catches on the
same try.
Lastly, remove some superfluous/vestigial casts from instruction operand
setters operating on BasicBlocks.
Reviewers: rnk, majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12108
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245797 91177308-0d34-0410-b5e6-96231b3b80d8
Some debug info was drastically out of date, from the days where we used
to emit a list of length one (with a single null entry) rather than an
empty list (or, more recently, no list at all) for list fields that have
no elements.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245796 91177308-0d34-0410-b5e6-96231b3b80d8
There was already a good error path for this. Added a test for it & made
a minor code change to ensure the error path was actually reached,
rather than crashing before we got that far.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245795 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
__shared__ variable may now emit undef value as initializer, do not
throw error on that.
Test Plan: test/CodeGen/NVPTX/global-addrspace.ll
Patch by Xuetian Weng
Reviewers: jholewinski, tra, jingyue
Subscribers: llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D12242
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245785 91177308-0d34-0410-b5e6-96231b3b80d8
If corresponding in-tree subdirectory exists, just ignore LLVM_EXTERNAL* stuff.
Otherwise, set LLVM_TOOL_*_BUILD ON/OFF properly according to LLVM_EXTERNAL_*.
This makes easier to walk among old revisions *without* deleteing CMakeCache.txt.
Before r242059, LLVM_EXTERNAL_* was working like;
if(EXISTS ${*_SOURCE_DIR}/CMakeLists.txt)
set(*_BUILD ON CACHE)
if(*_BUILD is ON)
add_subdirectory(*_SOURCE_DIR)
endif()
endif()
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245782 91177308-0d34-0410-b5e6-96231b3b80d8
Although the basic s_load_* instructions happen to use the same
opcode, some of the special case SMRD instructions have
different opcodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245775 91177308-0d34-0410-b5e6-96231b3b80d8
The main change is inverting the condition for the
operand class classes so that VT.Size == 16 uses VGPR_32
instead of 64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245764 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Merge functions previously relied on unsigned comparisons of pointer values to
order functions. This caused observable non-determinism in the compiler for
large bitcode programs. Basically, opt -mergefuncs program.bc | md5sum produces
different hashes when run repeatedly on the same machine. Differing output was
observed on three large bitcodes, but it was less frequent on the smallest file.
It is possible that this only manifests on the large inputs, hence remaining
undetected until now.
This patch fixes this by removing (almost, see below) all places where
comparisons between pointers are used to order functions. Most of these changes
are local, but the comparison of global values requires assigning an identifier
to each local in the order it is visited. This is very similar to the way the
comparison function identifies Value*'s defined within a function. Because the
order of visiting the functions and their subparts is deterministic, the
identifiers assigned to the globals will be as well, and the order of functions
will be deterministic.
With these changes, there is no more observed non-determinism. There is also
only minor slowdowns (negligible to 4%) compared to the baseline, which is
likely a result of the fact that global comparisons involve hash lookups and not
just pointer comparisons.
The one caveat so far is that programs containing BlockAddress constants can
still be non-deterministic. It is not clear what the right solution is here. In
particular, even if the global numbers are used to order by function, we still
need a way to order the BasicBlock*'s. Unfortunately, we cannot just bail out
and fail to order the functions or consider them equal, because we require a
total order over functions. Note that programs with BlockAddress constants are
relatively rare, so the impact of leaving this in is minor as long as this pass
is opt-in.
Author: jrkoenig
Reviewers: nlewycky, jfb, dschuff
Subscribers: jevinskie, llvm-commits, chapuni
Differential revision: http://reviews.llvm.org/D12168
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245762 91177308-0d34-0410-b5e6-96231b3b80d8
SCEV expansion can invalidate previously expanded values. For example
in SCEVExpander::ReuseOrCreateCast, if we already have the requested
cast value but it's not at the desired location, a new cast is inserted
and the old cast will be invalidated.
Therefore, when expanding the bounds for the pointers, a later entry can
invalidate the IR value for an earlier one. The fix is to store a value
handle rather than the value itself.
The newly added test has a more detailed description of how the bug
triggers.
This bug can have a negative but potentially highly variable performance
impact in Loop Distribution. Because one of the bound values was
invalidated and is an undef expression now, InstCombine is free to
transform the array overlap check:
Start0 <= End1 && Start1 <= End0
into:
Start0 <= End1
So depending on the runtime location of the arrays, we would detect a
conflict and fall back on the original loop of the versioned loop.
Also tested compile time with SPEC2006 LTO bc files.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245760 91177308-0d34-0410-b5e6-96231b3b80d8
This allows us to remove a bunch of code in LTOCodeGenerator and llvm-lto
and has the side effect of improving error handling in the libLTO C API.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245756 91177308-0d34-0410-b5e6-96231b3b80d8
We can wait on either VM, EXP or LGKM.
The waits are independent.
Without this patch, a wait inserted because of one of them
would also wait for all the previous others.
This patch makes s_wait only wait for the ones we need for the next
instruction.
Here's an example of subtle perf reduction this patch solves:
This is without the patch:
buffer_load_format_xyzw v[8:11], v0, s[44:47], 0 idxen
buffer_load_format_xyzw v[12:15], v0, s[48:51], 0 idxen
s_load_dwordx4 s[44:47], s[8:9], 0xc
s_waitcnt lgkmcnt(0)
buffer_load_format_xyzw v[16:19], v0, s[52:55], 0 idxen
s_load_dwordx4 s[48:51], s[8:9], 0x10
s_waitcnt vmcnt(1)
buffer_load_format_xyzw v[20:23], v0, s[44:47], 0 idxen
The s_waitcnt vmcnt(1) is useless.
The reason it is added is because the last
buffer_load_format_xyzw needs s[44:47], which was issued
by the first s_load_dwordx4. It waits for all VM
before that call to have finished.
Internally after every instruction, 3 counters (for VM, EXP and LGTM)
are updated after every instruction. For example buffer_load_format_xyzw
will
increase the VM counter, and s_load_dwordx4 the LGKM one.
Without the patch, for every defined register,
the current 3 counters are stored, and are used to know
how long to wait when an instruction needs the register.
Because of that, the s[44:47] counter includes that to use the register
you need to wait for the previous buffer_load_format_xyzw.
Instead this patch stores only the counters that matter for the
register,
and puts zero for the other ones, since we don't need any wait for them.
Patch by: Axel Davy
Differential Revision: http://reviews.llvm.org/D11883
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245755 91177308-0d34-0410-b5e6-96231b3b80d8
The original checkin was buggy, this change has a fix.
Original commit message:
[InstCombine] Transform A & (L - 1) u< L --> L != 0
Summary:
This transform is never a pessimization at the IR level (since it
replaces an `icmp` with another), and has potentiall payoffs:
1. It may make the `icmp` fold away or become loop invariant.
2. It may make the `A & (L - 1)` computation dead.
This shows up in Java, in range checks generated by array accesses of
the form `a[i & (a.length - 1)]`.
Reviewers: reames, majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12210
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245753 91177308-0d34-0410-b5e6-96231b3b80d8
One variant of this method can be reused when parsing the quoted IR pointer
expressions in the machine memory operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245743 91177308-0d34-0410-b5e6-96231b3b80d8
