[PatternMatch] Add support for capture-and-match (NFC) (#149825)

When using PatternMatch, there is a common problem where we want to both
match something against a pattern, but also capture the
value/instruction for various reasons (e.g. to access flags).

Currently the two ways to do that is to either capture using
m_Value/m_Instruction and do a separate match on the result, or to use
the somewhat awkward `m_CombineAnd(m_XYZ, m_Value(V))` pattern.

This PR introduces to add a variant of `m_Value`/`m_Instruction` which
does both a capture and a match. `m_Value(V, m_XYZ)` is basically
equivalent to `m_CombineAnd(m_XYZ, m_Value(V))`.

I've ported two InstCombine files to this pattern as a sample.

0 files changed, 0 insertions, 0 deletions