llvm-svn: 338537

The functions `lookForDIEsToKeep` and `keepDIEAndDependencies` can have
some very deep recursion. This tackles part of this problem by removing
the recursion from `lookForDIEsToKeep` by turning it into a worklist.

The difficulty in doing so is the computation of incompleteness, which
depends on the incompleteness of its children. To compute this, we
insert "continuation markers" into the worklist. This informs the work
loop to (re)compute the incompleteness property of the DIE associated
with it (i.e. the parent of the previously processed DIE).

This patch should generate byte-identical output. Unfortunately it also
has some impact of performance, regressing by about 4% when processing
clang on my machine.

Differential revision: https://reviews.llvm.org/D48899

llvm-svn: 338536

llvm-svn: 338532

llvm-svn: 338530

llvm-svn: 338529

Getting the DWARF types section is only implemented for ELF object
files. We already disabled emitting debug types in clang (r337717), but
now we also report an fatal error (rather than crashing) when trying to
obtain this section in MC. Additionally we ignore the generate debug
types flag for unsupported target triples.

See PR38190 for more information.

Differential revision: https://reviews.llvm.org/D50057

llvm-svn: 338527

Summary:
Add _L to _LZ image intrinsic table mapping to table gen.
In ISelLowering check if image intrinsic has lod and if it's equal
to zero, if so remove lod and change opcode to equivalent mapped _LZ.

Change-Id: Ie24cd7e788e2195d846c7bd256151178cbb9ec71

Subscribers: arsenm, mehdi_amini, kzhuravl, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D49483

llvm-svn: 338523

llvm-svn: 338522

The DAG combiner logic to simplify AND masks in shift counts is invalid.
While it is true that the SystemZ shift instructions ignore all but the
low 6 bits of the shift count, it is still invalid to simplify the AND
masks while the DAG still uses the standard shift operators (which are
*not* defined to match the SystemZ instruction behavior).

Instead, this patch performs equivalent operations during instruction
selection. For completely removing the AND, this now happens via
additional DAG match patterns implemented by a multi-alternative
PatFrags. For simplifying a 32-bit AND to a 16-bit AND, the existing DAG
patterns were already mostly OK, they just needed an output XForm to
actually truncate the immediate value.

Unfortunately, the latter change also exposed a bug in TableGen: it
seems XForms are currently only handled correctly for direct operands of
the outermost operation node. This patch also fixes that bug by simply
recurring through the whole pattern. This should be NFC for all other
targets.

Differential Revision: https://reviews.llvm.org/D50096

llvm-svn: 338521

llvm-svn: 338516

llvm-svn: 338514

llvm-svn: 338513

Should fix the MSVC bots by explicitly invoking
llvm::make_reverse_iterator to remove ambiguity with
std::make_reverse_iterator.

llvm-svn: 338511

Follow-up for r338506 with some unrelated changes in formatting and
consistency.

llvm-svn: 338509

Differential Revision: https://reviews.llvm.org/D49243

llvm-svn: 338507

The DWARFDie is a lightweight utility wrapper that stores a pointer to a
compile unit and a debug info entry. Currently, its iterator (used for
walking over its children) stores a DWARFDie and returns a const
reference when dereferencing it.

When the iterator is modified (by incrementing or decrementing it), this
reference becomes invalid. This was happening when calling reverse on
it, because the std::reverse_iterator is keeping a temporary copy of the
iterator (see
https://en.cppreference.com/w/cpp/iterator/reverse_iterator for a good
illustration).

The relevant code in libcxx:

  reference operator*() const {_Iter __tmp = current; return *--__tmp;}

When dereferencing the reverse iterator, we decrement and return a
reference to a DWARFDie stored in the stack frame of this function,
resulting in UB at runtime.

This patch specifies the std::reverse_iterator for DWARFDie to do the
right thing.

Differential revision: https://reviews.llvm.org/D49679

llvm-svn: 338506

Select G_GLOBAL_VALUE for position dependent code.

Patch by Petar Avramovic.

Differential Revision: https://reviews.llvm.org/D49803

llvm-svn: 338499

llvm-svn: 338496

This means it will be installed also in builds configured with
LLVM_INSTALL_TOOLCHAIN_ONLY, such as the Windows packages.

llvm-svn: 338495

Summary:
This patch improves Inliner to provide causes/reasons for negative inline decisions.
1. It adds one new message field to InlineCost to report causes for Always and Never instances. All Never and Always instantiations must provide a simple message.
2. Several functions that used to return the inlining results as boolean are changed to return InlineResult which carries the cause for negative decision.
3. Changed remark priniting and debug output messages to provide the additional messages and related inline cost.
4. Adjusted tests for changed printing.

Patch by: yrouban (Yevgeny Rouban)


Reviewers: craig.topper, sammccall, sgraenitz, NutshellySima, shchenz, chandlerc, apilipenko, javed.absar, tejohnson, dblaikie, sanjoy, eraman, xbolva00

Reviewed By: tejohnson, xbolva00

Subscribers: xbolva00, llvm-commits, arsenm, mehdi_amini, eraman, haicheng, steven_wu, dexonsmith

Differential Revision: https://reviews.llvm.org/D49412

llvm-svn: 338494

Also add a test for it being unsupported for linux.

Differential Revision: https://reviews.llvm.org/D49929

llvm-svn: 338493

[X86] When looking for (CMOV C-1, (ADD (CTTZ X), C), (X != 0)) -> (ADD (CMOV (CTTZ X), -1, (X != 0)), C), make sure we really have a compare with 0.

It's not strictly required by the transform of the cmov and the add, but it makes sure we restrict it to the cases we know we want to match.

While there canonicalize the operand order of the cmov to simplify the matching and emitting code.

llvm-svn: 338492

This revision implements support for generating DWARFv5 .debug_addr section.
The implementation is pretty straight-forward: we just check the dwarf version
and emit section header if needed.

Reviewers: aprantl, dblaikie, probinson

Reviewed by: dblaikie

Differential Revision: https://reviews.llvm.org/D50005

llvm-svn: 338487

This patch intends to enable jump threading when a method whose return type is std::pair<int, bool> or std::pair<bool, int> is inlined.
For example, jump threading does not happen for the if statement in func.

std::pair<int, bool> callee(int v) {
  int a = dummy(v);
  if (a) return std::make_pair(dummy(v), true);
  else return std::make_pair(v, v < 0);
}

int func(int v) {
  std::pair<int, bool> rc = callee(v);
  if (rc.second) {
    // do something
  }

SROA executed before the method inlining replaces std::pair by i64 without splitting in both callee and func since at this point no access to the individual fields is seen to SROA.
After inlining, jump threading fails to identify that the incoming value is a constant due to additional instructions (like or, and, trunc).

This series of patch add patterns in InstructionSimplify to fold extraction of members of std::pair. To help jump threading, actually we need to optimize the code sequence spanning multiple BBs.
These patches does not handle phi by itself, but these additional patterns help NewGVN pass, which calls instsimplify to check opportunities for simplifying instructions over phi, apply phi-of-ops optimization to result in successful jump threading. 
SimplifyDemandedBits in InstCombine, can do more general optimization but this patch aims to provide opportunities for other optimizers by supporting a simple but common case in InstSimplify.

This first patch in the series handles code sequences that merges two values using shl and or and then extracts one value using lshr.

Differential Revision: https://reviews.llvm.org/D48828

llvm-svn: 338485

Only generate symbol difference expression if needed.

llvm-svn: 338484

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50128

llvm-svn: 338483

EFLAGS copy lowering.

If you have a branch of LLVM, you may want to cherrypick this. It is
extremely unlikely to hit this case empirically, but it will likely
manifest as an "impossible" branch being taken somewhere, and will be
... very hard to debug.

Hitting this requires complex conditions living across complex control
flow combined with some interesting memory (non-stack) initialized with
the results of a comparison. Also, because you have to arrange for an
EFLAGS copy to be in *just* the right place, almost anything you do to
the code will hide the bug. I was unable to reduce anything remotely
resembling a "good" test case from the place where I hit it, and so
instead I have constructed synthetic MIR testing that directly exercises
the bug in question (as well as the good behavior for completeness).

The issue is that we would mistakenly assume any SETcc with a valid
condition and an initial operand that was a register and a virtual
register at that to be a register *defining* SETcc...

It isn't though....

This would in turn cause us to test some other bizarre register,
typically the base pointer of some memory. Now, testing this register
and using that to branch on doesn't make any sense. It even fails the
machine verifier (if you are running it) due to the wrong register
class. But it will make it through LLVM, assemble, and it *looks*
fine... But wow do you get a very unsual and surprising branch taken in
your actual code.

The fix is to actually check what kind of SETcc instruction we're
dealing with. Because there are a bunch of them, I just test the
may-store bit in the instruction. I've also added an assert for sanity
that ensure we are, in fact, *defining* the register operand. =D

llvm-svn: 338481

we aren't incorrectly generating any of it when doing SLH.

There was a bug that only occured with SLH that very much looked like it
could be caused by bad unwind info, and so this was a prime suspect.
Turns out that everything is fine, but this way we'll *see* if we end
up, for example, putting things we shouldn't inside the prolog.

llvm-svn: 338480

It is necessary to generate fixups in .debug_line as relaxation is
enabled due to the address delta may be changed after relaxation.

DWARF will record the mappings of lines and addresses in
.debug_line section. It will encode the information using special
opcodes, standard opcodes and extended opcodes in Line Number
Program. I use DW_LNS_fixed_advance_pc to encode fixed length
address delta and DW_LNE_set_address to encode absolute address
to make it possible to generate fixups in .debug_line section.

Differential Revision: https://reviews.llvm.org/D46850

llvm-svn: 338477

Previously we were just visiting the blocks in the function in IR order, which
is rather arbitrary. Therefore we wouldn't always visit defs before uses, but
the translation code relies on this assumption in some places.

Only codegen change seen in tests is an elision of a redundant copy.

Fixes PR38396

llvm-svn: 338476

Differential Revision: https://reviews.llvm.org/D49874

llvm-svn: 338470

determination for mergeable sections into a small static function.

llvm-svn: 338469

mostly unused variable.

llvm-svn: 338468

Call shouldOutlineFromFunctionByDefault, isFunctionSafeToOutlineFrom,
getOutliningType, and getMachineOutlinerMBBFlags using the correct
TargetInstrInfo. And don't create a MachineFunction for a function
declaration.

The call to getOutliningCandidateInfo is still a little weird, but at
least the weirdness is explicitly called out.

Differential Revision: https://reviews.llvm.org/D49880

llvm-svn: 338465

Add test case for the simplification of `pow()` for vector types that D50035
enables.

llvm-svn: 338463

Disable ARMCodeGenPrepare by default again. It is causing verifier
failues in V8 that look like:

  Duplicate integer as switch case
  switch i32 %trunc, label %if.end13 [
    i32 0, label %cleanup36
    i32 0, label %if.then8
  ], !dbg !4981
  i32 0
  fatal error: error in backend: Broken function found, compilation aborted!

I will continue reducing the test case and send it along.

llvm-svn: 338452

After r338437, debug_ranges are no longer emitted. Previously, this was only
done for DWARF version 5 and above.

llvm-svn: 338448

  This patch implements basic support for parsing
  and dumping DWARFv5 .debug_addr section.

llvm-svn: 338447

Reword comments and minor code reformatting.

llvm-svn: 338446

Summary:
See binutils-gdb/bfd/elf.c, GNU objcopy also strips .stab* (STABS)
.line* (DWARF 1) .gnu.linkonce.wi.* (linkonce section for .debug_info) but
I'm not sure we need to be compatible with it.

Reviewers: dblaikie, alexshap, jakehehrlich, jhenderson

Reviewed By: alexshap, jakehehrlich

Subscribers: aprantl, JDevlieghere, jakehehrlich, llvm-commits

Differential Revision: https://reviews.llvm.org/D50100

llvm-svn: 338443