The motivating case is an infinite loop shown with a reduced test from:
https://llvm.org/PR51762
To solve this, I'm proposing we delete the most obviously broken part of this code.
The bug example shows a fundamental problem: we ask computeKnownBits if a transform
will be profitable, alter the code by creating new instructions, then rely on
computeKnownBits to return the same answer to actually eliminate instructions.
But there's no guarantee that the results will be the same between the 1st and 2nd
calls. In the infinite loop example, we get different answers, so we add
instructions that conflict with some other transform, and we're stuck.
There's at least one other problem visible in the test diff for
`@zext_or_masked_bit_test_uses`: the code doesn't check uses properly, so we can
end up with extra instructions created.
Last, it's not clear if this set of transforms actually improves analysis or
codegen. I spot-checked a few targets and don't see a clear win:
https://godbolt.org/z/x87EWovso
If we do see a regression from this change, codegen seems like the right place to
add a cmp -> bit-hack fold.
If this is too big of a step, we could limit the computeKnownBits calls by not
passing a context instruction and/or limiting the recursion. I checked that those
would stop the infinite loop for PR51762, but that won't guarantee that some other
example does not fall into the same loop.
Differential Revision: https://reviews.llvm.org/D109440
As discussed on the ticket, I'm intending to add additional 128->256 patterns when we have test coverage, but this addresses a known crash.
Differential Revision: https://reviews.llvm.org/D109434
Allow variable number of directories, as allowed by the
specification. NumberOfRvaAndSize will default to 16 if not specified,
as in the past.
Reviewed by: jhenderson
Differential Revision: https://reviews.llvm.org/D108825
I can't seem to wrap my head around the proper fix here,
we should be fine without this requirement, iff we can form this form,
but the naive attempt (https://reviews.llvm.org/D106317) has failed.
So just to unblock the release, put up a restriction.
Fixes https://bugs.llvm.org/show_bug.cgi?id=51125
For sve_fp_3op_p_zds_zx we have zero patterns downstream but the
intrinsic args can be added again if/when the patterns are implemented.
Identified in D109359.
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D109429
Don't outline machine instructions which are using jump table indexes
since they are materialized as local labels (like the already handled
case of constant pools).
Reviewed By: paquette
Differential Revision: https://reviews.llvm.org/D109436
The cross-compiled lldb-server targets are added to the lldb deps if
Android cross compilation is enabled.
Differential Revision: https://reviews.llvm.org/D109464
On Linux, LLDB depends on lldb-server at runtime (on Mac, the dependency on
a debug server presumably comes via the system debugserver), so I added it
to deps.
Differential Revision: https://reviews.llvm.org/D109463
This moves one mid-size function out of line, inlines the
trivial tcAnd/tcOr/tcXor/tcComplement methods into their only
caller, and moves the magic/umagic functions into SelectionDAG
since they are implementation details of its algorithm. This
also removes the unit tests for magic, but these are already
tested in the divide lowering logic for various targets.
This also upgrades some C style comments to C++.
Differential Revision: https://reviews.llvm.org/D109476
Similar to other code which handles creating the function frame.
If LR isn't live-in to the block that we're inserting the call into, we'll get
a MachineVerifier error.
This is a port of a combine which matches a pattern where a wide type scalar
value is stored by several narrow stores. It folds it into a single store or
a BSWAP and a store if the targets supports it.
Assuming little endian target:
i8 *p = ...
i32 val = ...
p[0] = (val >> 0) & 0xFF;
p[1] = (val >> 8) & 0xFF;
p[2] = (val >> 16) & 0xFF;
p[3] = (val >> 24) & 0xFF;
=>
*((i32)p) = val;
On CTMark AArch64 -Os this results in a good amount of savings:
Program before after diff
SPASS 412792 412788 -0.0%
kc 432528 432512 -0.0%
lencod 430112 430096 -0.0%
consumer-typeset 419156 419128 -0.0%
bullet 475840 475752 -0.0%
tramp3d-v4 367760 367628 -0.0%
clamscan 383388 383204 -0.0%
pairlocalalign 249764 249476 -0.1%
7zip-benchmark 570100 568860 -0.2%
sqlite3 287628 286920 -0.2%
Geomean difference -0.1%
Differential Revision: https://reviews.llvm.org/D109419
This ensures error messages from gtest includes the raw text of both
sides of the comparison - otherwise all gtest can report is the text of
the expression source, without any information about the values or how
they differ.
It's a common error in an API - to try to open an empty file, so it
seems like a reasonable FileError to produce "hey, you tried to open an
empty file" and to handle it the same way as any other file error.
This moves all the private implementation details to the bottom of
the header, and pushes all the "make an APInt" stuff up to the top.
This is in prep for making other changes to spiff up APInt a bit.
We were returning a tuple when all but one caller only cared about one piece of the return value. That one caller can inline the complexity, and we can simplify all other uses.
Previously the CodeExtractor created exit stubs, and the subsequent return value of the outlined function based on the order of out-of-region blocks after splitting any phi nodes, and collecting the blocks to be outlined. This could cause differences in order if there was a difference of exit block phi nodes between the two regions. This patch moves the collection of the output target blocks to be before this occurs, so that the assignment of target block to output value will be the same, regardless of the contents of the output block.
Reviewers: paquette, roelofs
Differential Revision: https://reviews.llvm.org/D108657
Since i128 isn't a legal C type on RV32, I don't believe
libgcc implements these functions for RV32. compiler-rt
does implement them because i128 support is enabled
in order to handle long double.
This is consistent with 32-bit X86 and ARM.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D109383
Users of delinearization assume that the the offset into the array element is zero. In most cases it will indeed be zero, but if it is not, the delinearization has to fail since it violates that assumption without the API even allowing to signal to the caller that the by offset is non-zero.
This bug caused Polly to miscompile blender (526.blender_r from SPEC CPU 2017) in -polly-process-unprofitable mode. The SCEV expression incorrectly delinearized has been reduced in the test case byte_offset.ll. The dropped offset into the array element of size 4 (a float) is ((sext i32 %mul7.i4534 to i64) + {(sext i32 %i1 to i64),+,((sext i32 (1 + ((1 + %shl.i.i) * (1 + %shl.i.i)) + %shl.i.i) to i64) * (sext i32 %i1 to i64))}<%for.body703>). This significant component was just dropped, and the wrong pointer was computed when regenerating code from the remaining delinearized subscripts. This occurred during blender's subsurface scattering implementation. As a result, blender's rendering diverged from the reference image.
Patch D108885 would also fix the API.
Reviewed By: bmahjour
Differential Revision: https://reviews.llvm.org/D109133
Since we might end up using multiple threads when logging information in the DWARFTransformer, the handleDie() method must use the supplied stream named "OS" when logging warnings and errors. When we use multiple threads, we log to a thread specific stream buffer and then use a mutex to ensure our output doesn't overlap when we emit warnings and errors after a thread is done.
Differential Revision: https://reviews.llvm.org/D109401
Make the following changes in order to support opaque pointers in SROA:
* Generate i8 GEPs for opaque pointers.
* Explicitly enforce that promotable allocas only have stores of
the alloca type -- previously this was implicitly enforced.
* Replace a check for pointer element type with load/store type.
Differential Revision: https://reviews.llvm.org/D109259
The implementation is mostly copied from MemDepAnalysis. We want to look
at all loads and stores to the same pointer operand. Bitcasts and zero
GEPs of a pointer are considered the same pointer value. We choose the
most dominating instruction.
Since updating MemorySSA with invariant.group is non-trivial, for now
handling of invariant.group is not cached in any way, so it's part of
the walker. The number of loads/stores with invariant.group is small for
now anyway. We can revisit if this actually noticeably affects compile
times.
To avoid invariant.group affecting optimized uses, we need to have
optimizeUsesInBlock() not use invariant.group in any way.
Co-authored-by: Piotr Padlewski <prazek@google.com>
Reviewed By: asbirlea, nikic, Prazek
Differential Revision: https://reviews.llvm.org/D109134
None of this logic has anything to do with SCEV's internals, it just uses the existing public APIs. As a result, we can move the code from ScalarEvolution.cpp/hpp to Delinearization.cpp/hpp with only minor changes.
This was discussed in advance on today's loop opt call. It turned out to be easy as hoped.
integer 0/1 for the operand of bundle "clang.arc.attachedcall"
https://reviews.llvm.org/D102996 changes the operand of bundle
"clang.arc.attachedcall". This patch makes changes to llvm that are
needed to handle the new IR.
This should make it easier to understand what the IR is doing and also
simplify some of the passes as they no longer have to translate the
integer values to the runtime functions.
Differential Revision: https://reviews.llvm.org/D103000
D104143 introduced canonical value numbering between regions, which allows for the easy identification of items across a region, eliminating the need in the outliner to create parallel lists of instructions for each region, and replace output values in a less convoluted way.
Additionally, in a future commit, the output values will not necessarily be recorded values from the region itself, it could be a combination value where the actual value being output is a PHINode instead. This new method allows us to handle the replacement of the output value to the stored value with the corresponding item in the same place for both normal output values, and PHINode outputs instead of handling the different types of outputs in different locations.
Reviewers: paquette, roelofs
Differential Revision: https://reviews.llvm.org/D108656
This patch changes SPMDization to not trigger for regions with no
parallelism. Otherwise, this will introduce unnecessary barriers that
will slow the single-threaded region down.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D109438
Otherwise we end up with an extra conditional jump, following by an
unconditional jump off the end of a function. ie.
bb.0:
BT32rr ..
JCC_1 %bb.4 ...
bb.1:
BT32rr ..
JCC_1 %bb.2 ...
JMP_1 %bb.3
bb.2:
...
bb.3.unreachable:
bb.4:
...
Should be equivalent to:
bb.0:
BT32rr ..
JCC_1 %bb.4 ...
JMP_1 %bb.2
bb.1:
bb.2:
...
bb.3.unreachable:
bb.4:
...
This can occur since at the higher level IR (Instruction) SwitchInsts
are required to have BBs for default destinations, even when it can be
deduced that such BBs are unreachable.
For most programs, this isn't an issue, just wasted instructions since the
unreachable has been statically proven.
The x86_64 Linux kernel when built with CONFIG_LTO_CLANG_THIN=y fails to
boot though once D106056 is re-applied. D106056 makes it more likely
that correlation-propagation (CVP) can deduce that the default case of
SwitchInsts are unreachable. The x86_64 kernel uses a binary post
processor called objtool, which emits this warning:
vmlinux.o: warning: objtool: cfg80211_edmg_chandef_valid()+0x169: can't
find jump dest instruction at .text.cfg80211_edmg_chandef_valid+0x17b
I haven't debugged precisely why this causes a failure at boot time, but
fixing this very obvious jump off the end of the function fixes the
warning and boot problem.
Link: https://bugs.llvm.org/show_bug.cgi?id=50080
Fixes: https://github.com/ClangBuiltLinux/linux/issues/679
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1440
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D109103
This should have been the 4 byte version in the first place. Unfortunatelly there is no easy way to add a test as both the 1 byte and 4 byte version are printed as 'jmp' in the assembly code.
Reviewed By: kda
Differential Revision: https://reviews.llvm.org/D109453
Sanjay Patel