Running `llc -verify-dom-info` on the attached testcase results in a
crash in the verifier, due to a stale dominator tree.

i.e.

  DominatorTree is not up to date!
  Computed:
  =============================--------------------------------
  Inorder Dominator Tree:
    [1] %safe_mod_func_uint8_t_u_u.exit.i.i.i {0,7}
      [2] %lor.lhs.false.i61.i.i.i {1,2}
      [2] %safe_mod_func_int8_t_s_s.exit.i.i.i {3,6}
        [3] %safe_div_func_int64_t_s_s.exit66.i.i.i {4,5}

  Actual:
  =============================--------------------------------
  Inorder Dominator Tree:
    [1] %safe_mod_func_uint8_t_u_u.exit.i.i.i {0,9}
      [2] %lor.lhs.false.i61.i.i.i {1,2}
      [2] %safe_mod_func_int8_t_s_s.exit.i.i.i {3,8}
        [3] %safe_div_func_int64_t_s_s.exit66.i.i.i {4,5}
        [3] %safe_mod_func_int8_t_s_s.exit.i.i.i.lor.lhs.false.i61.i.i.i_crit_edge {6,7}

This is because in `SelectionDAGIsel` we split critical edges without
updating the corresponding dominator for the function (and we claim
in `MachineFunctionPass::getAnalysisUsage()` that the domtree is preserved).

We could either stop preserving the domtree in `getAnalysisUsage`
or tell `splitCriticalEdge()` to update it.
As the second option is easy to implement, that's the one I chose.

Differential Revision:  https://reviews.llvm.org/D33800

llvm-svn: 304742

This ensures that we can emit the ObjC Image Info structure on COFF and
ELF as well.  The frontend already would attempt to emit this
information but would get dropped when generating assembly or an object
file.

llvm-svn: 304736

Other calls to DAGCombiner::*PromoteOperand check the result, but here it could cause an assertion in getNode. 
Falling back to any extend in this case instead of failing outright seems correct to me.

No test case because:
The failure was triggered by an out of tree backend. In order to trigger it, a backend would need to overload 
TargetLowering::IsDesirableToPromoteOp to return true for a type for which ISD::SIGN_EXTEND_INREG is marked 
illegal. In tree, only X86 overloads and sometimes returns true for MVT::i16 yet it marks 
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16  , Legal);.

Patch by Jacob Young!

Differential Revision: https://reviews.llvm.org/D33633

llvm-svn: 304723

This patch provides a means to specify section-names for global variables,
functions and static variables, using #pragma directives.
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""

Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33413

llvm-svn: 304704

llvm-svn: 304635

llvm-svn: 304627

Adjust code to look more like the code in LivePhysRegs and port over the
fix for LivePhysRegs from r304001 and adapt to the new CSR management in
MachineRegisterInfo.

llvm-svn: 304622

[CodeGen] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 304621

We'd called this "vm state" in the early days, but have long since standardized on calling it "deopt" in line with the operand bundle tag.  Fix a few cases we'd missed.

llvm-svn: 304607

This pass allows to run the register scavenging independently of
PrologEpilogInserter to allow targeted testing.

Also adds some basic register scavenging tests.

llvm-svn: 304606

Prior to this patch we used to not touch the LiveRegMatrix while doing
live-range splitting. In other words, when live-range splitting was
occurring, the LiveRegMatrix was not reflecting the changes.
This is generally fine because it means the query to the LiveRegMatrix
will be conservately correct. However, when decisions are taken based on
what is going to happen on the interferences (e.g., when we spill a
register and know that it is going to be available for another one), we
might hit an assertion that the color used for the assignment is still
in use.

This patch makes sure the changes on the live-ranges are properly
reflected in the LiveRegMatrix, so the assertions don't break.
An alternative could have been to remove the assertion, but it would
make the invariants of the code and the general reasoning more
complicated in my opnion.

http://llvm.org/PR33057

llvm-svn: 304603

Use the initializeXXX method to initialize the RABasic pass in the
pipeline. This enables us to take advantage of the .mir infrastructure.

llvm-svn: 304602

These parts do not depend on any PrologEpilogInserter logic and
therefore better fits RegisterScaveging.cpp.

llvm-svn: 304596

llvm-svn: 304569

While doing so, clarify the comments and update them to reflect current reality.

Note: I'm going to let this sit for a week or so before adding further verification.  I want to give this time to cycle through bots and merge it into our downstream tree before pushing this further.
llvm-svn: 304565

This initial patch doesn't actually do much useful. It's just to show where the new code goes. Once this is in, I'll extend the verification logic to check more useful properties.

For those curious, the more complicated version of this patch already found one very suspicious thing.

Differential Revision: https://reviews.llvm.org/D33819

llvm-svn: 304564

When a global may be preempted it needs to be accessed directly, instead of
indirectly through a MergedGlobals symbol, for the preemption to work.

This fixes PR33136.

Differential Revision: https://reviews.llvm.org/D33727

llvm-svn: 304537

llvm-svn: 304532

The recursive implementation of findNonImmUse may overflow stack
on extremely long use chains. This patch replaces it with an equivalent
iterative implementation.

Reviewed By: bogner

Differential Revision: https://reviews.llvm.org/D33775

llvm-svn: 304522

[CodeGen] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 304495

The AArch64 backend marks calls that involve aggregate function
arguments as having an implicit def of SP. We already have the same
workaround in LiveDebugValues and in DbgValueHistoryCalculator for SP
clobbers in register masks. This adds register defs to the list.

Fixes rdar://problem/30361929 and Swift SR-3851.

llvm-svn: 304471

Reorder CombineTo Calls to prevent references to stale/deleted SDNodes which caused undue assertions.

Reviewers: dbabokin

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D31625

llvm-svn: 304460

These are only integer operations.

llvm-svn: 304417

Summary:
This is a problem uncovered by stage2 testing. ADDCARRY end up being generated on target that do not support it.

The patch that introduced the problem has other patches layed on top of it, so we want to fix the issue rather than revert it to avoid creating a lor of churn.

A regression test will be added shortly, but this is committed as this in order to get the build back to green promptly.

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D33770

llvm-svn: 304409

Summary:
This is a continuation of the work started in D29872 . Passing the carry down as a value rather than as a glue allows for further optimizations. Introducing setcccarry makes the use of addc/subc unecessary and we can start the removal process.

This patch only introduce the optimization strictly required to get the same level of optimization as was available before nothing more.

Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D33374

llvm-svn: 304404

Summary: This pattern is no very useful per se, but it exposes optimization for toehr patterns that wouldn't kick in otherwize. It's very common and worth optimizing for.

Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32756

llvm-svn: 304402

Summary:
This enables further transforms.

Depends on D32916

Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32925

llvm-svn: 304401

Summary: LiveRangeShrink pass moves instruction right after the definition with the same BB if the instruction and its operands all have more than one use. This pass is inexpensive and guarantees optimal live-range within BB.

Reviewers: davidxl, wmi, hfinkel, MatzeB, andreadb

Reviewed By: MatzeB, andreadb

Subscribers: hiraditya, jyknight, sanjoy, skatkov, gberry, jholewinski, qcolombet, javed.absar, krytarowski, atrick, spatel, RKSimon, andreadb, MatzeB, mehdi_amini, mgorny, efriedma, davide, dberlin, llvm-commits

Differential Revision: https://reviews.llvm.org/D32563

llvm-svn: 304371

The values are marked as livein in the successor blocks so marking them
as killed or dead was wrong.

llvm-svn: 304366

llvm-svn: 304365

We should have a single call site entry with no landing pad. This
indicates that no EH action should be taken and the unwinder should
unwind to the next frame.

We currently don't recognize __gxx_personality_seh0 as a known
personality, so we forcibly emit a table, and that table was wrong. This
was filed as PR33220. Now we emit a correct table for that personality.
The next step is to recognize that we can completely skip the table for
this personality.

llvm-svn: 304363

It seems not all of our bots have a std::vector::erase() taking a
const_iterator (even though that seems to be part of C++11) attempt to
workaround.

llvm-svn: 304349

After transforming FP to ST registers:
- Do not add the ST register to the livein lists, they are reserved so
  we do not need to track their liveness.
- Remove the FP registers from the livein lists, they don't have defs or
  uses anymore and so are not live.
- (The setKillFlags() call is moved to an earlier place as it relies on
   the FP registers still being present in the livein list.)

llvm-svn: 304342

Summary:
If we attempt to unfold an SUnit in ScheduleDAG that results in
finding an already scheduled load, we must should abort the
unfold as it will not improve scheduling.

This fixes PR32610.

Reviewers: jmolloy, sunfish, bogner, spatel

Subscribers: llvm-commits, MatzeB

Differential Revision: https://reviews.llvm.org/D32911

llvm-svn: 304321

This adds a callback to the LLVMTargetMachine that lets target indicate
that they do not pass the machine verifier checks in all cases yet.

This is intended to be a temporary measure while the targets are fixed
allowing us to enable the machine verifier by default with
EXPENSIVE_CHECKS enabled!

Differential Revision: https://reviews.llvm.org/D33696

llvm-svn: 304320

This patch does an inline expansion of memcmp.
It changes the memcmp library call into an inline expansion when the size is
known at compile time and is under a target specified threshold.
This expansion is implemented in CodeGenPrepare and expands into straight line
code. The target specifies a maximum load size and the expansion works by using
this size to load the two sources, compare, and exit early if a difference is
found. It also has a special case when the memcmp result is used in a compare
to zero equality.

Differential Revision: https://reviews.llvm.org/D28637

llvm-svn: 304313

Correct references to alignment of store which may be deleted in a
previous iteration of merge. Instead use first store that would be
merged.

Corrects pr33172's use-after-poison caught by ASan.

Reviewers: spatel, hfinkel, RKSimon

Reviewed By: RKSimon

Subscribers: thegameg, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D33686

llvm-svn: 304299

[CodeGen] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 304265

This was introduced a long time ago in r86583 when regmask operands
didn't exist. Nowadays the behavior hurts more than it helps. This
removes it.

llvm-svn: 304254

Summary:
AntiDepBreaker intends to add all live-outs, including the implicit
CSRs, in StartBlock. r299124 was done without understanding that
intention.

Now with the live-ins propagated correctly (D32464), we can revert this change.

Reviewers: MatzeB, qcolombet

Subscribers: nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D33697

llvm-svn: 304251