Follow-up build fix for rGae6f78824031

One of the bots objects to brace-initializing a tuple:

http://lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/43595/steps/build%20stag

Follow-up build fix for rGae6f78824031

One of the bots objects to brace-initializing a tuple:

http://lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/43595/steps/build%20stage%201/logs/stdio

As the tuple constructor is apparently explicit. Fall back to the (not
as pretty) explicit construction of a tuple. I'd thought this was
permitted behaviour; will investigate why this fails later.

show more ...

[LiveDebugValues] Delete unneeded copy constructor after D83047

It will suppress the implicitly-declared copy assignment operator in C++20.

[LiveDebugValues] Add instruction-referencing LDV implementation

This patch imports the instruction-referencing implementation of
LiveDebugValues proposed here:

http://lists.llvm.org/pipermail/ll

[LiveDebugValues] Add instruction-referencing LDV implementation

This patch imports the instruction-referencing implementation of
LiveDebugValues proposed here:

http://lists.llvm.org/pipermail/llvm-dev/2020-June/142368.html

The new implementation is unreachable in this patch, it's the next patch
that enables it behind a command line switch. Briefly, rather than
tracking variable locations by just their location as the 'VarLoc'
implementation does, this implementation does it by value:
* Each value defined in a function is numbered, and propagated through
dataflow,
* Each DBG_VALUE reads a machine value number from a machine location,
* Variable _values_ are propagated through dataflow,
* Variable values are translated back into locations, DBG_VALUEs
inserted to specify where those locations are.

The ultimate aim of this is to enable referring to variable values
throughout post-isel code, rather than locations. Those patches will
build on top of this new LiveDebugValues implementation in later patches
-- it can't be done with the VarLoc implementation as we don't have
value information, only locations.

Differential Revision: https://reviews.llvm.org/D83047

show more ...