(i == 5334 || i == 5335)
to:
((i & -2) == 5334)
This transformation has some incorrect side conditions. Specifically, the
transformation is only applied when the right-hand side constant (5334 in
the example) is a power of two not equal and not equal to the negated mask.
These side conditions were added in r258904 to fix PR26323. The correct side
condition is that: ((Constant & Mask) == Constant)[(5334 & -2) == 5334].
It's a little bit hard to see why these transformations are correct and what
the side conditions ought to be. Here is a CVC3 program to verify them for
64-bit values:
ONE : BITVECTOR(64) = BVZEROEXTEND(0bin1, 63);
x : BITVECTOR(64);
y : BITVECTOR(64);
z : BITVECTOR(64);
mask : BITVECTOR(64) = BVSHL(ONE, z);
QUERY( (y & ~mask = y) =>
((x & ~mask = y) <=> (x = y OR x = (y | mask)))
);
Please note that each pattern must be a dual implication (<--> or iff). One
directional implication can create spurious matches. If the implication is
only one-way, an unsatisfiable condition on the left side can imply a
satisfiable condition on the right side. Dual implication ensures that
satisfiable conditions are transformed to other satisfiable conditions and
unsatisfiable conditions are transformed to other unsatisfiable conditions.
Here is a concrete example of a unsatisfiable condition on the left
implying a satisfiable condition on the right:
mask = (1 << z)
(x & ~mask) == y --> (x == y || x == (y | mask))
Substituting y = 3, z = 0 yields:
(x & -2) == 3 --> (x == 3 || x == 2)
The version of this code before r258904 had no side-conditions and
incorrectly justified itself in comments through one-directional
implication.
Thanks to Chandler for the suggestion!
Author: Thomas Jablin (tjablin)
Reviewers: chandlerc majnemer hfinkel cycheng
http://reviews.llvm.org/D21417
llvm-svn: 272873
The backend has been around for years, it's pretty ridiculous that we can't
even use the preferred form for printing "MOV" aliases. Unfortunately, TableGen
can't handle the complex predicates when printing so it's a bunch of nasty C++.
Oh well.
llvm-svn: 272865
Summary:
[libFuzzer] Enable afl_driver to append stderr to a user specified file.
Append stderr of afl_driver to the file specified by the environmental variable
AFL_DRIVER_STDERR_DUPLICATE_FILENAME if it is set. This lets users see outputs
on crashes without rerunning crashing test cases (which won't work for crashes
that are difficult to reproduce). Before this patch, stderr would only be sent to afl-fuzz
and users would have no way of seeing it.
Reviewers: llvm-commits, aizatsky, kcc, vitalybuka
Subscribers: vitalybuka
Differential Revision: http://reviews.llvm.org/D21194
llvm-svn: 272858
Summary: This reverts the changes to Globals.cpp and IRMover.cpp in
"[IR] Copy comdats in GlobalObject::copyAttributesFrom" (D20631,
rL270743).
The DeadArgElim test is left unchanged, and we change DAE to explicitly
copy comdats.
The reverted change breaks copyAttributesFrom when the destination lives
in a different module from the source. The decision in D21255 was to
revert this patch and handle comdat copying separately from
copyAttributesFrom.
Reviewers: majnemer, rnk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21403
llvm-svn: 272855
Summary:
This is necessary to keep the verifier happy after bugpoint removes an
initializer from a global variable with a comdat annotation, because
globals without initializers may not have comdats.
Reviewers: majnemer, rnk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21274
llvm-svn: 272854
LoopVectorizationLegality holds a constant reference to LAI, so this
will have to be const as well.
Also added missed function comment.
llvm-svn: 272851
It was printing out nothing in this case.
llvm-objdump tries to disassemble sections a symbol at a time. In the case of a
fully stripped Mach-O executable the only symbol remaining in the (__TEXT,__text)
section is the special linker defined symbol __mh_execute_header . This
symbol is special in that while it is N_SECT symbol in the (__TEXT,__text)
its address is before the start of the (__TEXT,__text). It’s address is the
start of the __TEXT segment which is where the mach header is statically
linked. So the code in DisassembleMachO() needs to deal with this case specially.
rdar://26778273
llvm-svn: 272837
This patch makes CFLAA ignore non-pointer values, since we can now
sanely do that with the escaping/unknown attributes. Additionally,
StratifiedAttrs make more sense to sit on nodes than edges (since
they're properties of values, and ultimately end up on the nodes of
StratifiedSets). So, this patch puts said attributes on nodes.
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21387
llvm-svn: 272833
Of course the assembly was right but because the opcode was MOVZWi it was
encoded as "movz w16, #65535, lsl #32" which is an unallocated encoding and
would go horribly wrong on a CPU.
No idea how this bug survived this long. It seems nobody is using that aspect
of patchpoints.
llvm-svn: 272831
- We lacked a short unique identifier for a statistics, so I renamed the
current "Name" field that just contained the DEBUG_TYPE name of the
current file to DebugType and added a new "Name" field that contains
the C++ identifier of the statistic variable.
- Add the -stats-json option which outputs statistics in json format.
Differential Revision: http://reviews.llvm.org/D20995
llvm-svn: 272826
Emit a S_UDT record for typedefs. We still need to do something for
class types.
Differential Revision: http://reviews.llvm.org/D21149
llvm-svn: 272813
Summary: As per title. This completes the C API Attribute support.
Reviewers: Wallbraker, whitequark, echristo, rafael, jyknight
Subscribers: mehdi_amini
Differential Revision: http://reviews.llvm.org/D21365
llvm-svn: 272811
This allows us to emit native IR in Clang (next commit).
Also, update the intrinsic tests to show that codegen already knows how to handle
the IR that Clang will soon produce.
llvm-svn: 272806
We would fail to validate the type of the tan function which would cause
downstream users of isValidProtoForLibFunc to assert.
This fixes PR28143.
llvm-svn: 272802
Sean Silva