Created using spr 1.3.6-beta.1

This patch adds support for LLVM IR atomicrmw `fmaximum` and `fminimum`
instructions.

These mirror the `llvm.maximum.*` and `llvm.minimum.*` instructions, but
are atomic and use IEEE754 2019 handling for NaNs, which is different to
`fmax` and `fmin`. See:
     https://llvm.org/docs/LangRef.html#llvm-minimum-intrinsic
for more details.

Future changes will allow this LLVM IR to be lowered to specialised
assembler instructions on suitable targets, such as AArch64.

Reverts llvm/llvm-project#136759 due to bad interaction with c792b25e4

This patch adds support for LLVM IR atomicrmw `fmaximum` and `fminimum`
instructions.

These mirror the `llvm.maximum.*` and `llvm.minimum.*` instructions, but
are atomic and use IEEE754 2019 handling for NaNs, which is different to
`fmax` and `fmin`. See:
     https://llvm.org/docs/LangRef.html#llvm-minimum-intrinsic
for more details.

Future changes will allow this LLVM IR to be lowered to specialised
assembler instructions on suitable targets, such as AArch64.

To make sure that a larger range on the call-site does not suppress
information from a smaller range at the declaration.

In [1], Nikita Popov suggested that during lowering 'unreachable' insn
should not generate extra code for naked functions, and this applies to
all architectures. Note that for naked functions, 'unreachable' insn is
necessary in IR since the basic block needs a terminator to end.

This patch checked whether a function is naked function or not. If it is
a naked function, 'unreachable' insn will not generate ISD::TRAP.

  [1] https://github.com/llvm/llvm-project/pull/131731

Co-authored-by: Yonghong Song <yonghong.song@linux.dev>

`convergencectrl` doesn't imply any memory access.
Closes https://github.com/llvm/llvm-project/issues/129856.

Relative to the previous attempt this includes two fixes:
 * Adjust callCapturesBefore() to not skip captures(ret: address,
    provenance) arguments, as these will not count as a capture
    at the call-site.
 * When visiting uses during stack slot optimization, don't skip
    the ModRef check for passthru captures. Calls can both modref
    and be passthru for captures.

------

This extends CaptureTracking to support inferring non-trivial
CaptureInfos. The focus of this patch is to only support FunctionAttrs,
other users of CaptureTracking will be updated in followups.

The key API changes here are:

* DetermineUseCaptureKind() now returns a UseCaptureInfo where the UseCC
component specifies what is captured at that Use and the ResultCC
component specifies what may be captured via the return value of the
User. Usually only one or the other will be used (corresponding to
previous MAY_CAPTURE or PASSTHROUGH results), but both may be set for
call captures.
* The CaptureTracking::captures() extension point is passed this
UseCaptureInfo as well and then can decide what to do with it by
returning an Action, which is one of: Stop: stop traversal.
ContinueIgnoringReturn: continue traversal but don't follow the
instruction return value. Continue: continue traversal and follow the
instruction return value if it has additional CaptureComponents.

For now, this patch retains the (unsound) special logic for comparison
of null with a dereferenceable pointer. I'd like to switch key code to
take advantage of address/address_is_null before dropping it.

This PR mainly intends to introduce necessary API changes and basic
inference support, there are various possible improvements marked with
TODOs.

This reverts commit 0fab404ee874bc5b0c442d1841c7d2005c3f8729.
Seems to break LTO builds of clang on Windows, see comments on
https://github.com/llvm/llvm-project/pull/125880