- _Float16 is now accepted by Clang.

- The half IR type is fully handled by the backend.

- These values are passed in FP registers and converted to/from float around
  each operation.

- Compiler-rt conversion functions are now built for s390x including the missing
  extendhfdf2 which was added.

Fixes #50374

On processors supporting vector registers and SIMD instructions, enable
i128 as legal type in VRs. This allows many operations to be implemented
via native instructions directly in VRs (including add, subtract,
logical operations and shifts). For a few other operations (e.g.
multiply and divide, as well as atomic operations), we need to move the
i128 value back to a GPR pair to use the corresponding instruction
there. Overall, this is still beneficial.

The patch includes the following LLVM changes:
- Enable i128 as legal type
- Set up legal operations (in SystemZInstrVector.td)
- Custom expansion for i128 add/subtract with carry
- Custom expansion for i128 comparisons and selects
- Support for moving i128 to/from GPR pairs when required
- Handle 128-bit integer constant values everywhere
- Use i128 as intrinsic operand type where appropriate
- Updated and new test cases

In addition, clang builtins are updated to reflect the intrinsic operand
type changes (which also improves compatibility with GCC).

A rare case where coalescing resulted in a hh32 (high32 of high64 of vector
register) subreg usage caused getSubReg() to fail as the vector reg does not
have that subreg in its subregs list, but rather h32 which was expected to
also act as hh32. See link below for the discussion when solving this.

Patch By: critson

Reviewed By: uweigand

Fixes: https://github.com/llvm/llvm-project/issues/61390

This commit adds the initial changes to the SystemZ target
description for the XPLINK 64-bit calling convention on z/OS.
Additions include:

 - a new predicate IsTargetXPLINK64
 - different register allocation order
 - generaton of nopr after a call

Reviewed-by: uweigand

Differential Revision: https://reviews.llvm.org/D96887

This adds the FPC (floating-point control register) as a reserved
physical register and models its use by SystemZ instructions.

Note that only the current rounding modes and the IEEE exception
masks are modeled.  *Changes* of the FPC due to exceptions (in
particular the IEEE exception flags and the DXC) are not modeled.

At this point, this patch is mostly NFC, but it will prevent
scheduling of floating-point instructions across SPFC/LFPC etc.

llvm-svn: 360570

to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

Change
  subreg_r32  -> subreg_h32
  subreg_r64  -> subreg_h64
  subreg_hr32 -> subreg_hh32

The subregisters subreg_r32 and subreg_r64 were added to emphasize the
fact that modifying these subregisters may clobber the entire register.
This is not necessarily the case for subreg_h32, et al.

However, the ability to compose subreg_h64 with subreg_r32, and with
subreg_h32 and subreg_l32 at the same time makes the compositions be
treated as non-overlapping (leading to problems when tracking subreg
liveness). See D50468 for more details.

Differential Revision: https://reviews.llvm.org/D50725

llvm-svn: 339778

Currently, an instruction setting the condition code is linked to
the instruction using the condition code via a "glue" link in the
SelectionDAG.  This has a number of drawbacks; in particular, it
means the same CC cannot be used by multiple users.  It also makes
it more difficult to efficiently implement SADDO et. al.

This patch changes the back-end to represent CC dependencies as
normal values during SelectionDAG matching, along the lines of
how this is handled in the X86 back-end already.

In addition to the core mechanics of updating all relevant patterns,
this requires a number of additional changes:

- We now need to be able to spill/restore a CC value into a GPR
  if necessary.  This means providing a copyPhysReg implementation
  for moves involving CC, and defining getCrossCopyRegClass.

- Since we still prefer to avoid such spills, we provide an override
  for IsProfitableToFold to avoid creating a merged LOAD / ICMP if
  this would result in multiple users of the CC.

- combineCCMask no longer requires a single CC user, and no longer
  need to be careful about preventing invalid glue/chain cycles.

- emitSelect needs to be more careful in marking CC live-in to
  the basic block it generates.  Also, we can now optimize the
  case of multiple subsequent selects with the same condition
  just like X86 does.

llvm-svn: 331202

AnyReg is just for the assembler and it is better to have it as not
allocatable in order to simplify (make more intuitive) the RegPressureSets.

Review: Ulrich Weigand
llvm-svn: 327715