[RISCV][CFI] add function epilogue cfi information (#110810)

This patch adds CFI instructions in the function epilogue.

Before patch:
addi sp, s0, -32
ld ra, 24(sp) # 8-byte Folded Reload
ld s

[RISCV][CFI] add function epilogue cfi information (#110810)

This patch adds CFI instructions in the function epilogue.

Before patch:
addi sp, s0, -32
ld ra, 24(sp) # 8-byte Folded Reload
ld s0, 16(sp) # 8-byte Folded Reload
ld s1, 8(sp) # 8-byte Folded Reload
addi sp, sp, 32
ret

After patch:
addi sp, s0, -32
.cfi_def_cfa sp, 32
ld ra, 24(sp) # 8-byte Folded Reload
ld s0, 16(sp) # 8-byte Folded Reload
ld s1, 8(sp) # 8-byte Folded Reload
.cfi_restore ra
.cfi_restore s0
.cfi_restore s1
addi sp, sp, 32
.cfi_def_cfa_offset 0
ret

This functionality is already present in `riscv-gcc`, but it’s not in
`clang` and this slightly impairs the `lldb` debugging experience, e.g.
backtrace.

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[RISCV] Inline Assembly: RVC constraint and N modifier (#112561)

This change implements support for the `cr` and `cf` register
constraints (which allocate a RVC GPR or RVC FPR respectively), and th

[RISCV] Inline Assembly: RVC constraint and N modifier (#112561)

This change implements support for the `cr` and `cf` register
constraints (which allocate a RVC GPR or RVC FPR respectively), and the
`N` modifier (which prints the raw encoding of a register rather than
the name).

The intention behind these additions is to make it easier to use inline
assembly when assembling raw instructions that are not supported by the
compiler, for instance when experimenting with new instructions or when
supporting proprietary extensions outside the toolchain.

These implement part of my proposal in riscv-non-isa/riscv-c-api-doc#92

As part of the implementation, I felt there was not enough coverage of
inline assembly and the "in X" floating-point extensions, so I have
added more regression tests around these configurations.

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[RISCV] Move compressible registers to the beginning of the FP allocation order.

We don't have very many compressible FP instructions, just load and store.
These instruction require the FP register

[RISCV] Move compressible registers to the beginning of the FP allocation order.

We don't have very many compressible FP instructions, just load and store.
These instruction require the FP register to be f8-f15.

This patch changes the FP allocation order to prioritize f10-f15 first.
These are also the FP argument registers. So I allocated them in reverse
order starting at f15 to avoid taking the first argument registers.
This appears to match gcc allocation order.

Reviewed By: asb

Differential Revision: https://reviews.llvm.org/D146488

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[RISCV] Convert some tests to opaque pointers (NFC)

[RISCV] More correctly ignore Zfinx register classes in getRegForInlineAsmConstraint.

Until Zfinx is supported in CodeGen we need to convert all Zfinx
register classes to GPR.

Remove the zfinx-type

[RISCV] More correctly ignore Zfinx register classes in getRegForInlineAsmConstraint.

Until Zfinx is supported in CodeGen we need to convert all Zfinx
register classes to GPR.

Remove the zfinx-types.ll test which didn't test anything meaningful
since -mattr=zfinx isn't implemented completely in llc.

Follow up to D93298.

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[RISCV] update zfh and zfhmin extention to v1.0

`zfh` and `zfhmin` have been ratified, with version 1.0.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D117098

[RISCV] Honor the VT when converting float point register names to register class for inline assembly.

It appears the code here was written for the inline asm clobbering
a specific register, but it

[RISCV] Honor the VT when converting float point register names to register class for inline assembly.

It appears the code here was written for the inline asm clobbering
a specific register, but it also gets used for named input and
output registers.

For the input and output case, we should honor the VT so we
don't insert conversion instructions around the inline assembly.

For the clobber, case we need to pick the largest register class.

Reviewed By: asb, jrtc27

Differential Revision: https://reviews.llvm.org/D117279

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[RISCV] Add basic Zfh inline assembly tests. NFC

The abi name test shows incorrect fcvt.d.h, fcvt.h.d, fcvt.f.h,
and fcvt.h.f instructions around the inline assembly.