Fixes llvm#97147.

Transforming `(mul x, -(2^(N-M) - 1) * 2^M)` to `(sub (shl x, M), (shl
x, N))` will cause overflow when N is 32 and M is 31. I still added
checks for all scenarios, even other scenarios, don't seem to cause overflow.

(cherry picked from commit 4a96803)

llvm#93754)

LLVM's build system does the right thing but LLVM_SYSTEM_LIBS ends up
containing the shared library. Emit the static library instead when
appropriate.

With LLVM_USE_STATIC_ZSTD, before:

khuey@zhadum:~/dev/llvm-project/build$ ./bin/llvm-config --system-libs
-lrt -ldl -lm -lz -lzstd -lxml2

after:

khuey@zhadum:~/dev/llvm-project/build$ ./bin/llvm-config --system-libs
-lrt -ldl -lm -lz /usr/local/lib/libzstd.a -lxml2

(cherry-picked from 0f24a46)

Expose the memory addressing to simplify checking stack spill/restore manipulation codegen

(cherry picked from commit 8270485)

…(x),c)) if the pattern has multiple uses

Fixes llvm#97533 crash where we hit a case where the root node had referenced the original zext node, which we then deleted - hopefully I can come up with a better solution, but the codegen changes don't look too bad atm (pulls out a shift from some complex LEA nodes that shared the scaled index).

(cherry picked from commit e975ff0)

For llvm#97702.

(cherry picked from commit e7bfd4d)

…value (llvm#97711)

If there is a single store, then loads must either load the stored value
or uninitialized memory (undef). If the stored value may be poison, then
replacing an uninitialized memory load with it would be incorrect. Fall
back to the generic code in that case.

This PR only fixes the case where there is a literal poison store -- the
case where the value is non-trivially poison will still get miscompiled
by phi simplification later, see llvm#96631.

Fixes llvm#97702.

(cherry picked from commit f58930f)

In llvm#97711 the single-store optimization was disabled for the case
where the value is potentially poison, as this may produce incorrect
results for loads of uninitialized memory.

However, this resulted in compile-time regressions. Address these
by still allowing the single-store optimization to occur in cases
where the store dominates the load, as we know that such a load
will always read initialized memory.

(cherry picked from commit daaea12)