- _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

This pr includes fixes for original pr##116642.
Implementation for __builtin_setjmp and __builtin_longjmp for SystemZ..

This reverts commit 030bbc92a705758f1131fb29cab5be6d6a27dd1f.

Implementation for __builtin_setjmp and __builtin_longjmp for SystemZ.

This patch adds support for the ADA (associated data area), doing the following:

-Creates the ADA table to handle displacements
-Emits the ADA section in the SystemZAsmPrinter
-Lowers the ADA_ENTRY node into the appropriate load instruction

Differential Revision: https://reviews.llvm.org/D153788

This reverts commit 9df0f66af5462e23216eae31aedbd4d2f459cc3d.

- Creates the ADA table to handle displacements
- Emits the ADA section in the SystemZAsmPrinter
- Lowers the ADA_ENTRY node into the appropriate load instruction

Differential Revision: https://reviews.llvm.org/D153788

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

The backward register scavenger has correct register
liveness information. PEI should leverage the backward register scavenger.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D137574

Identified with modernize-use-override.