Seeing how we can't generate any debug intrinsics any more: delete a
variety of codepaths where they're handled. For the most part these are
plain deletions, in others I've tweaked comments to remain coherent, or
added a type to (what was) type-generic-lambdas.

This isn't all the DbgInfoIntrinsic call sites but it's most of the
simple scenarios.

Co-authored-by: Nikita Popov <github@npopov.com>

Bail out for non ConstantExpr constants in
isSimpleEnoughValueToCommitHelper to prevent crash for non-ConstantExpr
constants

PR: https://github.com/llvm/llvm-project/pull/143400

The global ctor evaluator tries to evalute function calls where the call
function type and function type do not match, by performing bitcasts.
This currently causes a crash when calling a void function with non-void
return type.

I've opted to remove this functionality entirely rather than fixing this
specific case. With opaque pointers, there shouldn't be a legitimate use
case for this anymore, as we don't need to look through pointer type
casts. Doing other bitcasts is very iffy because it ignores ABI
considerations. We should at least leave adjusting the signatures to
make them line up to InstCombine (which also does some iffy things, but
is at least somewhat more constrained).

Fixes https://github.com/llvm/llvm-project/issues/118725.

Identified with misc-include-cleaner.

If the memset is large, checking every single byte of the global
may be very slow. Add an upper bound on the size of memset we
handle.

For the common special case of memset zeroinitializer to zero,
add a fastpath that checks just that and is not length limited.

Fixes https://github.com/llvm/llvm-project/issues/62191.

This patch replaces the uses of PointerUnion.is function by llvm::isa,
PointerUnion.get function by llvm::cast, and PointerUnion.dyn_cast by
llvm::dyn_cast_if_present. This is according to the FIXME in
the definition of the class PointerUnion.

This patch does not remove them as they are being used in other
subprojects.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D148449

Many llvm/IR/* files have been migrated by other contributors.
This migrates most remaining files.

Relax the check to allow evaluation of atomic loads
(but still skip volatile loads).

Test plan:
1/ ninja check-llvm check-clang
2/ Bootstrapped LLVM/Clang pass tests

Differential revision: https://reviews.llvm.org/D130211

Relax the check to allow evaluation of atomic stores
(but still skip volatile stores).

Test plan:
1/ ninja check-llvm check-clang
2/ Bootstrapped LLVM/Clang pass tests

Differential revision: https://reviews.llvm.org/D129841