Summary:
This change teaches DSE that the atomic memory intrinsics can be overwriten
partially in the same way as the non-atomic forms. Specifically, that the
atomic memcpy & memset can be shortened at the end and that the atomic memset
can be shortened at the beginning, if they partially overwritten
by later stores.
Reviewers: mkazantsev, skatkov, apilipenko, efriedma, rsmith, spatel, filcab, sanjoy
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45584
llvm-svn: 331991
Fixes bug https://bugs.llvm.org/show_bug.cgi?id=37339.
InlineAsm is only uniqued if the FunctionTypes are exactly the
same, while cmpTypes() for example considers all pointer types
in the default address space to be the same. For this reason
the end of cmpInlineAsm() can be reached.
This patch replaces the unreachable assertion with a check that
the function types are not identical.
Differential Revision: https://reviews.llvm.org/D46495
Reviewers: jfb
llvm-svn: 331990
Clang 6.0 was updated to create these intrinsics rather than
libcalls or fcmp/select, but the backend wasn't prepared to
handle that optimally.
This bug is not the primary reason for PR37403:
https://bugs.llvm.org/show_bug.cgi?id=37403
...but it's probably more important for x86 perf.
llvm-svn: 331988
Summary:
The combine in rebuildSetCC may be combined to another
node leaving our references stale. Keep a handle on
it to avoid stale references.
Fixes PR36602.
Reviewers: dbabokin, RKSimon, eli.friedman, davide
Subscribers: hiraditya, uabelho, JesperAntonsson, qcolombet, llvm-commits
Differential Revision: https://reviews.llvm.org/D46404
llvm-svn: 331985
The print format was causing at least 2 unit-test failures from r331971.
The signed/unsigned comparison warnings only appeared to affect two lines but
it was unclear whether it might just pop up on other lines, so I have been
explicit in all the literals in the tests.
There were other bot unit-test failures that I am still investigating.
llvm-svn: 331978
Summary:
Operand 0 is the condition, not the true value.
Use op 1 and op 2 as the correct values.
Reviewers: george.burgess.iv, nlopes, efriedma
Reviewed By: george.burgess.iv
Subscribers: craig.topper, rjmccall, lebedev.ri, llvm-commits
Differential Revision: https://reviews.llvm.org/D46343
llvm-svn: 331976
Put in a conservatively correct estimate for now. Avoids miscompiling
clang in FDO mode. This is really tricky to trigger in reality as
basically all interesting cases will be folded away by computeKnownBits
earlier, I was unable to find a reasonably small test case.
llvm-svn: 331975
A non-alloc note section should not have a PT_NOTE program header.
Found while linking ghc (Haskell compiler) with lld on FreeBSD.
ghc emits a .debug-ghc-link-info note section (as the name suggests, it
contains link information) as a SHT_NOTE section without SHF_ALLOC set.
For this case ld.bfd does not emit a PT_NOTE segment for the
.debug-ghc-link-info section. lld previously emitted a PT_NOTE with
p_vaddr = 0 and FreeBSD's rtld segfaulted when trying to parse a note at
address 0.
llvm.org/pr37361
Differential Revision: https://reviews.llvm.org/D46623
llvm-svn: 331973
Reviewed by: ruiu, grimar, espindola
Differential Revision: https://reviews.llvm.org/D44562
Summary:
r331971 changes the debug line parser interface to report LLVM errors in an
interface that different executables can use, rather than always being printed
directly as warnings to stderr. This change allows LLD to make use of the new
interface and call its own warning methods to report problems.
llvm-svn: 331972
Reviewed by: dblaikie, JDevlieghere, espindola
Differential Revision: https://reviews.llvm.org/D44560
Summary:
The .debug_line parser previously reported errors by printing to stderr and
return false. This is not particularly helpful for clients of the library code,
as it prevents them from handling the errors in a manner based on the calling
context. This change switches to using llvm::Error and callbacks to indicate
what problems were detected during parsing, and has updated clients to handle
the errors in a location-specific manner. In general, this means that they
continue to do the same thing to external users. Below, I have outlined what
the known behaviour changes are, relating to this change.
There are two levels of "errors" in the new error mechanism, to broadly
distinguish between different fail states of the parser, since not every
failure will prevent parsing of the unit, or of subsequent unit. Malformed
table errors that prevent reading the remainder of the table (reported by
returning them) and other minor issues representing problems with parsing that
do not prevent attempting to continue reading the table (reported by calling a
specified callback funciton). The only example of this currently is when the
last sequence of a unit is unterminated. However, I think it would be good to
change the handling of unrecognised opcodes to report as minor issues as well,
rather than just printing to the stream if --verbose is used (this would be a
subsequent change however).
I have substantially extended the DwarfGenerator to be able to handle
custom-crafted .debug_line sections, allowing for comprehensive unit-testing
of the parser code. For now, I am just adding unit tests to cover the basic
error reporting, and positive cases, and do not currently intend to test every
part of the parser, although the framework should be sufficient to do so at a
later point.
Known behaviour changes:
- The dump function in DWARFContext now does not attempt to read subsequent
tables when searching for a specific offset, if the unit length field of a
table before the specified offset is a reserved value.
- getOrParseLineTable now returns a useful Error if an invalid offset is
encountered, rather than simply a nullptr.
- The parse functions no longer use `WithColor::warning` directly to report
errors, allowing LLD to call its own warning function.
- The existing parse error messages have been updated to not specifically
include "warning" in their message, allowing consumers to determine what
severity the problem is.
- If the line table version field appears to have a value less than 2, an
informative error is returned, instead of just false.
- If the line table unit length field uses a reserved value, an informative
error is returned, instead of just false.
- Dumping of .debug_line.dwo sections is now implemented the same as regular
.debug_line sections.
- Verbose dumping of .debug_line[.dwo] sections now prints the prologue, if
there is a prologue error, just like non-verbose dumping.
As a helper for the generator code, I have re-added emitInt64 to the
AsmPrinter code. This previously existed, but was removed way back in r100296,
presumably because it was dead at the time.
This change also requires a change to LLD, which will be committed separately.
llvm-svn: 331971
I was considering modifying this function, so I wrote some tests to make
sure I don't regress its behavior. I am not sure if I will actually
proceed with the modifications, but the tests seem useful nonetheless.
llvm-svn: 331966
This is unnecessary for AVX512VL supporting CPUs like SKX. We can just emit a 128-bit masked load/store here no matter what. The backend will widen it to 512-bits on KNL CPUs.
Fixes the frontend portion of PR37386. Need to fix the backend to optimize the new sequences well.
llvm-svn: 331958
Summary:
The Itanium ABI requires that the type info for pointer-to-incomplete types to have internal linkage, so that it doesn't interfere with the type info once completed. Currently it also marks the type info name as internal as well. However, this causes a bug with the STL implementations, which use the type info name pointer to perform ordering and hashing of type infos.
For example:
```
// header.h
struct T;
extern std::type_info const& Info;
// tu_one.cpp
#include "header.h"
std::type_info const& Info = typeid(T*);
// tu_two.cpp
#include "header.h"
struct T {};
int main() {
auto &TI1 = Info;
auto &TI2 = typeid(T*);
assert(TI1 == TI2); // Fails
assert(TI1.hash_code() == TI2.hash_code()); // Fails
}
```
This patch fixes the STL bug by emitting the type info name as linkonce_odr when the type-info is for a pointer-to-incomplete type.
Note that libc++ could fix this without a compiler change, but the quality of fix would be poor. The library would either have to:
(A) Always perform strcmp/string hashes.
(B) Determine if we have a pointer-to-incomplete type, and only do strcmp then. This would require an ABI break for libc++.
Reviewers: rsmith, rjmccall, majnemer, vsapsai
Reviewed By: rjmccall
Subscribers: smeenai, cfe-commits
Differential Revision: https://reviews.llvm.org/D46665
llvm-svn: 331957
Summary:
Enumerating /proc/<pid>/task/ dir Linux may stop if thread is dead. In this case
we miss some alive threads and can report false memory leaks.
To solve this issue we repeat enumeration if the last thread is dead.
Do detect dead threads same way as proc_task_readdir we use
/proc/<pid>/task/<tid>/status.
Similarly it also ends enumeration of if proc_fill_cache fails, but in this case
Linux sets inode to 1 (Bad block).
And just in case re-list threads if we had to call internal_getdents more than
twice or result takes more than half of the buffer.
Reviewers: eugenis, dvyukov, glider
Subscribers: llvm-commits, kubamracek
Differential Revision: https://reviews.llvm.org/D46517
llvm-svn: 331953
During simplification umax we trigger isKnownPredicate twice. As a first attempt it
tries the induction. To do that it tries to get post increment of SCEV.
Re-writing the SCEV may result in simplification of umax. If the SCEV contains a lot
of umax operations this recursion becomes very slow.
The added test demonstrates the slow behavior.
To resolve this we use only simple ways to check whether the predicate is known.
Reviewers: sanjoy, mkazantsev
Reviewed By: sanjoy
Subscribers: lebedev.ri, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D46046
llvm-svn: 331949
Previously we emitted something like
rotl(x, n) {
n &= bitwidth-1;
return n != 0 ? ((x << n) | (x >> (bitwidth - n)) : x;
}
We use a select to avoid the undefined behavior on the (bitwidth - n) shift.
The middle and backend don't really recognize this as a rotate and end up emitting a cmov or control flow because of the select.
A better pattern is (x << (n & mask)) | (x << (-n & mask)) where mask is bitwidth - 1.
Fixes the main complaint in PR37387. There's still some work to be done if the user writes that sequence directly on a short or char where type promotion rules can prevent it from being recognized. The builtin is emitting direct IR with unpromoted types so that isn't a problem for it.
Differential Revision: https://reviews.llvm.org/D46656
llvm-svn: 331943
Lit creates malformed xml when the test case has an & in the name.
Escape those correctly.
This also adds a test case which I will add other nasty encoding issues to in some followup commits.
llvm-svn: 331942
Const/local/shared address spaces are all < 4GB and we can always use
32-bit pointers to access them. This has substantial performance impact
on kernels that uses shared memory for intermediary results.
The feature is disabled by default.
Differential Revision: https://reviews.llvm.org/D46147
llvm-svn: 331941
The option enables use of 32-bit pointers for accessing
const/local/shared memory. The feature is disabled by default.
Differential Revision: https://reviews.llvm.org/D46148
llvm-svn: 331938
Daniel Neilson