Traversing PHI nodes is natural with the genericValueTraversal but also
a bit tricky. The problem is similar to the ones we have seen in AAAlign
and AADereferenceable, namely that we continue to increase the range in
each iteration. We use a pessimistic approach here to stop the
iterations. Nevertheless, optimistic information can now be propagated
through a PHI node.
The change is performed as stated by the FIXME and the tests are
adjusted. All changes look fine to me and values can be inferred as
undef without it being an error.
Casts can be handled natively by the ConstantRange class. We do limit it
to extends for now as we assume an integer type in different locations.
A TODO and a test case with a FIXME was added to remove that restriction
in the future.
Using sign extend forces the adjacent element to either all zeros
or all ones. But all ones is a NAN. So that doesn't seem like a
great idea.
Trying to work on supporting this with strict FP where NAN would
definitely be bad.
When the FP exists, the FP base CFI directive offset should take the size of variable arguments into account.
Differential Revision: https://reviews.llvm.org/D73862
Vector indexing with a constant index should be folded out in the
legalizer, but this was accidentally falling through. This would
produce the indexing operation with $noreg. Handle this case as a
dynamic index just in case a bug like this happens again in the
future.
We were failing to find constants that were casted. I feel like the
artifact combiner should have folded the constant in the trunc before
the custom lowering, but that doesn't happen.
Reverts part of 6524a7a2b9. Since that
commit, the expansion was ignoring the actual save exec register
produced by the instruction, and looking at other instructions. I do
not understand why it was looking at other instructions, but relying
on this scan was wrong.
Fixes verifier errors after SI_IF is tail duplicated, which should be
correct to do. The results were fed into a phi, which was lowered to
the S_MOV_B64_term instructions.
Fix issue mentioned on rGe82e17d4d4ca - non-AVX512BW targets failed to concatenate 256-bit rotations back to 512-bits (split during shuffle lowering as they don't have v32i16/v64i8 types).
The flag isn't used, but I believe this matches the MOV32r0 that
would be created by the table emitter. This should allow this node
to be CSEed with any others created by the table.
As noted on PR44379, we didn't attempt to lower vector shuffles using bit rotations on XOP/AVX512F targets.
This patch lowers to uniform ISD:ROTL nodes - ROTR isn't supported by XOP and they are interchangeable for constant values anyway.
There might be cases where targets without ISD:ROTL support would benefit from this (expanding to SRL+SHL+OR), which I'll investigate in a future patch.
Also, non-AVX512BW targets fail to concatenate 256-bit rotations back to 512-bits (split during shuffle lowering as they don't have v32i16/v64i8 types).
A vselect+strictfp node is not equivalent to a masked operation.
The exceptions of the strictfp node are not masked by a vselect
after it so we can't match it to a masked operation.
We already had a hack in IsLegalToFold to prevent these patterns from
matching. This patch removes that hack and removes the patterns.
We have several bug reports that could be characterized as "reducing scalarization",
and this topic was also raised on llvm-dev recently:
http://lists.llvm.org/pipermail/llvm-dev/2020-January/138157.html
...so I'm proposing that we deal with these patterns in a new, lightweight IR vector
pass that runs before/after other vectorization passes.
There are 4 alternate options that I can think of to deal with this kind of problem
(and we've seen various attempts at all of these), but they all have flaws:
InstCombine - can't happen without TTI, but we don't want target-specific
folds there.
SDAG - too late to assist other vectorization passes; TLI is not equipped
for these kind of cost queries; limited to a single basic block.
CGP - too late to assist other vectorization passes; would need to re-implement
basic cleanups like CSE/instcombine.
SLP - doesn't fit with existing transforms; limited to a single basic block.
This initial patch/transform is based on existing code in AggressiveInstCombine:
we walk backwards through the function looking for a pattern match. But we diverge
from that cost-independent IR canonicalization pass by using TTI to decide if the
vector alternative is profitable.
We probably have at least 10 similar bug reports/patterns (binops, constants,
inserts, cheap shuffles, etc) that would fit in this pass as follow-up enhancements.
It's possible that we could iterate on a worklist to fix-point like InstCombine does,
but it's safer to start with a most basic case and evolve from there, so I didn't
try to do anything fancy with this initial implementation.
Differential Revision: https://reviews.llvm.org/D73480
When I have symlinked builddir on Fedora 31 x86_64 I get:
FAIL: test_libraries_svr4_libs_present (TestGdbRemoteLibrariesSvr4Support.TestGdbRemoteLibrariesSvr4Support)
----------------------------------------------------------------------
...
File "lldb/packages/Python/lldbsuite/test/tools/lldb-server/libraries-svr4/TestGdbRemoteLibrariesSvr4Support.py", line 106, in
libraries_svr4_libs_present
self.assertIn(self.getBuildDir() + "/" + lib, libraries_svr4_names)
AssertionError:
'/home/jkratoch/redhat/llvm-monorepo-clangassertsymlink/lldb-test-build.noindex/tools/lldb-server/libraries-svr4/TestGdbRemoteLibrariesSvr4Support.test_libraries_svr4_libs_present/libsvr4lib_a.so' not found in ['/home/jkratoch/redhat/llvm-monorepo/lldb/packages/Python/lldbsuite/test/tools/lldb-server/libraries-svr4/linux-vdso.so.1', '/quad/home/jkratoch/redhat/llvm-monorepo-clangassertsymlink/lldb-test-build.noindex/tools/lldb-server/libraries-svr4/TestGdbRemoteLibrariesSvr4Support.test_libraries_svr4_libs_present/libsvr4lib_a.so', '/quad/home/jkratoch/redhat/llvm-monorepo-clangassertsymlink/lldb-test-build.noindex/tools/lldb-server/libraries-svr4/TestGdbRemoteLibrariesSvr4Support.test_libraries_svr4_libs_present/libsvr4lib_b".so', '/usr/lib64/libdl-2.30.so', '/usr/lib64/libstdc++.so.6.0.27', '/usr/lib64/libm-2.30.so', '/usr/lib64/libgcc_s-9-20190827.so.1', '/usr/lib64/libc-2.30.so', '/usr/lib64/ld-2.30.so']
Config=x86_64-/quad/home/jkratoch/redhat/llvm-monorepo-clangassertsymlink/bin/clang-11
----------------------------------------------------------------------
Differential Revision: https://reviews.llvm.org/D74295
The LoopExtractor created new functions (by definition), which violates
the restrictions of a LoopPass.
The correct implementation of this pass should be as a ModulePass.
Includes reverting rL82990 implications on the LoopExtractor.
Fixes PR3082 and PR8929.
Differential Revision: https://reviews.llvm.org/D69069
Implement protection against the stack clash attack [0] through inline stack
probing.
Probe stack allocation every PAGE_SIZE during frame lowering or dynamic
allocation to make sure the page guard, if any, is touched when touching the
stack, in a similar manner to GCC[1].
This extends the existing `probe-stack' mechanism with a special value `inline-asm'.
Technically the former uses function call before stack allocation while this
patch provides inlined stack probes and chunk allocation.
Only implemented for x86.
[0] https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt
[1] https://gcc.gnu.org/ml/gcc-patches/2017-07/msg00556.html
This a recommit of 39f50da2a3 with proper LiveIn
declaration, better option handling and more portable testing.
Differential Revision: https://reviews.llvm.org/D68720
Implement protection against the stack clash attack [0] through inline stack
probing.
Probe stack allocation every PAGE_SIZE during frame lowering or dynamic
allocation to make sure the page guard, if any, is touched when touching the
stack, in a similar manner to GCC[1].
This extends the existing `probe-stack' mechanism with a special value `inline-asm'.
Technically the former uses function call before stack allocation while this
patch provides inlined stack probes and chunk allocation.
Only implemented for x86.
[0] https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt
[1] https://gcc.gnu.org/ml/gcc-patches/2017-07/msg00556.html
This a recommit of 39f50da2a3 with proper LiveIn
declaration, better option handling and more portable testing.
Differential Revision: https://reviews.llvm.org/D68720
Johannes Doerfert