The fix introduces segfaults and clobbers the value to be stored when
the atomic sequence loops.
Revert "[Target/MIPS] Kill dead code, no functional change intended."
This reverts commit r296153.
Revert "Recommit "[mips] Fix atomic compare and swap at O0.""
This reverts commit r296134.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297380 91177308-0d34-0410-b5e6-96231b3b80d8
entire SCC before iterating on newly-introduced call edges resulting
from any inlined function bodies.
This more closely matches the behavior of the old PM's inliner. While it
wasn't really clear to me initially, this behavior is actually essential
to the inliner behaving reasonably in its current design.
Because the inliner is fundamentally a bottom-up inliner and all of its
cost modeling is designed around that it often runs into trouble within
an SCC where we don't have any meaningful bottom-up ordering to use. In
addition to potentially cyclic, infinite inlining that we block with the
inline history mechanism, it can also take seemingly simple call graph
patterns within an SCC and turn them into *insanely* large functions by
accidentally working top-down across the SCC without any of the
threshold limitations that traditional top-down inliners use.
Consider this diabolical monster.cpp file that Richard Smith came up
with to help demonstrate this issue:
```
template <int N> extern const char *str;
void g(const char *);
template <bool K, int N> void f(bool *B, bool *E) {
if (K)
g(str<N>);
if (B == E)
return;
if (*B)
f<true, N + 1>(B + 1, E);
else
f<false, N + 1>(B + 1, E);
}
template <> void f<false, MAX>(bool *B, bool *E) { return f<false, 0>(B, E); }
template <> void f<true, MAX>(bool *B, bool *E) { return f<true, 0>(B, E); }
extern bool *arr, *end;
void test() { f<false, 0>(arr, end); }
```
When compiled with '-DMAX=N' for various values of N, this will create an SCC
with a reasonably large number of functions. Previously, the inliner would try
to exhaust the inlining candidates in a single function before moving on. This,
unfortunately, turns it into a top-down inliner within the SCC. Because our
thresholds were never built for that, we will incrementally decide that it is
always worth inlining and proceed to flatten the entire SCC into that one
function.
What's worse, we'll then proceed to the next function, and do the exact same
thing except we'll skip the first function, and so on. And at each step, we'll
also make some of the constant factors larger, which is awesome.
The fix in this patch is the obvious one which makes the new PM's inliner use
the same technique used by the old PM: consider all the call edges across the
entire SCC before beginning to process call edges introduced by inlining. The
result of this is essentially to distribute the inlining across the SCC so that
every function incrementally grows toward the inline thresholds rather than
allowing the inliner to grow one of the functions vastly beyond the threshold.
The code for this is a bit awkward, but it works out OK.
We could consider in the future doing something more powerful here such as
prioritized order (via lowest cost and/or profile info) and/or a code-growth
budget per SCC. However, both of those would require really substantial work
both to design the system in a way that wouldn't break really useful
abstraction decomposition properties of the current inliner and to be tuned
across a reasonably diverse set of code and workloads. It also seems really
risky in many ways. I have only found a single real-world file that triggers
the bad behavior here and it is generated code that has a pretty pathological
pattern. I'm not worried about the inliner not doing an *awesome* job here as
long as it does *ok*. On the other hand, the cases that will be tricky to get
right in a prioritized scheme with a budget will be more common and idiomatic
for at least some frontends (C++ and Rust at least). So while these approaches
are still really interesting, I'm not in a huge rush to go after them. Staying
even closer to the existing PM's behavior, especially when this easy to do,
seems like the right short to medium term approach.
I don't really have a test case that makes sense yet... I'll try to find a
variant of the IR produced by the monster template metaprogram that is both
small enough to be sane and large enough to clearly show when we get this wrong
in the future. But I'm not confident this exists. And the behavior change here
*should* be unobservable without snooping on debug logging. So there isn't
really much to test.
The test case updates come from two incidental changes:
1) We now visit functions in an SCC in the opposite order. I don't think there
really is a "right" order here, so I just update the test cases.
2) We no longer compute some analyses when an SCC has no call instructions that
we consider for inlining.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297374 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a machine verifier issue where a instruction was using a invalid
register. The return pseudo is expanded and has the return address
register added to it. The return register may have been spuriously
mark as killed earlier.
This partially resolves PR/27458
Thanks to Quentin Colombet for reporting the issue!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297372 91177308-0d34-0410-b5e6-96231b3b80d8
With this, it shows up as an attribute in YAML and non-printable characters
are properly removed by GlobalValue::getRealLinkageName.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297362 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In a .symver assembler directive like:
.symver name, name2@@nodename
"name2@@nodename" should get the same symbol binding as "name".
While the ELF object writer is updating the symbol binding for .symver
aliases before emitting the object file, not doing so when the module
inline assembly is handled by the RecordStreamer is causing the wrong
behavior in *LTO mode.
E.g. when "name" is global, "name2@@nodename" must also be marked as
global. Otherwise, the symbol is skipped when iterating over the LTO
InputFile symbols (InputFile::Symbol::shouldSkip). So, for example,
when performing any *LTO via the gold-plugin, the versioned symbol
definition is not recorded by the plugin and passed back to the
linker. If the object was in an archive, and there were no other symbols
needed from that object, the object would not be included in the final
link and references to the versioned symbol are undefined.
The llvm-lto2 tests added will give an error about an unused symbol
resolution without the fix.
Reviewers: rafael, pcc
Reviewed By: pcc
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D30485
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297332 91177308-0d34-0410-b5e6-96231b3b80d8
!type metadata can not be dropped. An alternative to this is adding
!type metadata from the replaced globals to the replacement, but that
may weaken type tests and make them slower at the same time.
The merged global gets !dbg metadata from replaced globals, and can
end up with multiple debug locations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297327 91177308-0d34-0410-b5e6-96231b3b80d8
This commit changes the BumpPtrAllocator for suffix tree nodes to a SpecificBumpPtrAllocator.
Before, node construction was leaking memory because of the DenseMap in SuffixTreeNodes.
Changing this to a SpecificBumpPtrAllocator allows this memory to properly be released.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297319 91177308-0d34-0410-b5e6-96231b3b80d8
When the array indexes are all determined by GVN to be constants,
a call is made to constant-folding to optimize/simplify the address
computation.
The constant-folding, however, makes a mistake in that it sometimes reads
back stale Idxs instead of NewIdxs, that it re-computed in previous iteration.
This leads to incorrect addresses coming out of constant-folding to GEP.
A test case is included. The error is only triggered when indexes have particular
patterns that the stale/new index updates interplay matters.
Reviewers: Daniel Berlin
Differential Revision: https://reviews.llvm.org/D30642
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297317 91177308-0d34-0410-b5e6-96231b3b80d8
We already have a function create_directories() which can create
an entire tree, and remove() which can remove an empty directory,
but we do not have remove_directories() which can remove an entire
tree. This patch adds such a function.
Because removing a directory tree can have dangerous consequences
when the tree contains a directory symlink, the patch here updates
the existing directory_iterator construct to optionally not follow
symlinks (previously it would always follow symlinks). The delete
algorithm uses this flag so that for symlinks, only the links are
removed, and not the targets.
On Windows this is implemented with SHFileOperation, which also
does not recurse into symbolic links or junctions.
Differential Revision: https://reviews.llvm.org/D30676
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297314 91177308-0d34-0410-b5e6-96231b3b80d8
Analyzing larger trees is extremely difficult with the current debug output so
this adds GraphTraits and DOTGraphTraits on top of the VectorizableTree data
structure. We can now display the SLP trees with Graphviz as in
https://reviews.llvm.org/F3132765.
I decorated the graph where a value needs to be gathered for one reason or
another. These are the red nodes.
There are other improvement I am planning to make as I work through my case
here. For example, I would also like to mark nodes that need to be extracted.
Differential Revision: https://reviews.llvm.org/D30731
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297303 91177308-0d34-0410-b5e6-96231b3b80d8
Because IRBuilder performs constant-folding, it's not guaranteed that an
instruction in the original loop map to an instruction in the vector loop. It
could map to a constant vector instead. The handling of first-order recurrences
was incorrectly making this assumption when setting the IRBuilder's insert
point.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297302 91177308-0d34-0410-b5e6-96231b3b80d8
When extracting a bitfield from the high register in a register pair,
the final offset should be relative to the high register (for 32-bit
extracts).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297288 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: By using reg_nodbg_empty() to determine if a function can be
treated as a leaf function or not, we miss the case when the register
pair L0_L1 is used but not L0 by itself. This has the effect that
use_all_i32_regs(), a test in reserved-regs.ll which tries to use all
registers, gets treated as a leaf function.
Reviewers: jyknight, venkatra
Reviewed By: jyknight
Subscribers: davide, RKSimon, sepavloff, llvm-commits
Differential Revision: https://reviews.llvm.org/D27089
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297285 91177308-0d34-0410-b5e6-96231b3b80d8
Recommitting patch which was previously reverted in r297159. These
changes should address the casting issues.
The original patch enables dbg.value intrinsics to be attached to
newly inserted PHI nodes.
Differential Review: https://reviews.llvm.org/D30701
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297269 91177308-0d34-0410-b5e6-96231b3b80d8
After inspection, it's an UB in our code base. Someone cast a var-arg
function pointer to a non-var-arg one. :/
Re-commit r296771 to continue testing on the patch.
Sorry for the trouble!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297256 91177308-0d34-0410-b5e6-96231b3b80d8
If there is only one successor, and that successor only
has one predecessor the wait can obviously be delayed until
uses or the end of the next block. This avoids code quality
regressions when there are trivial fallthrough blocks inserted
for structurization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297251 91177308-0d34-0410-b5e6-96231b3b80d8
When doing arcp optimization with a constant denominator,
this was leaving behind rcps with constant inputs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297248 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This will allow future patches to inspect the details of the LLT. The implementation is now split between
the Support and CodeGen libraries to allow TableGen to use this class without introducing layering concerns.
Thanks to Ahmed Bougacha for finding a reasonable way to avoid the layering issue and providing the version of this patch without that problem.
The problem with the previous commit appears to have been that TableGen was including CodeGen/LowLevelType.h instead of Support/LowLevelTypeImpl.h.
Reviewers: t.p.northover, qcolombet, rovka, aditya_nandakumar, ab, javed.absar
Subscribers: arsenm, nhaehnle, mgorny, dberris, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D30046
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297241 91177308-0d34-0410-b5e6-96231b3b80d8
In my refactoring I introduced a bug where we were using the reference size instead of the offset size for DW_FORM_strp and similar forms.
This patch resolves the error and adds a test case testing all the DWARF forms for DWARF2 AddrSize 8. There is similar coverage already in the DWARFDebugInfoTest sources that covers the parser. Once I migrate the DWARFGenerator APIs to be built on the YAML tools they will be fully covered under the same tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297230 91177308-0d34-0410-b5e6-96231b3b80d8
