[ValueTracking] tighten up matchMinMax(); NFCI

This is similar to what the caller (matchSelectPattern()) does. In all
cases where we succeed in matching a min/max pattern, the values in
that pattern will be the values of the 'select', so hoist that and
remove a bunch of duplicated code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292725 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed