This was originally done to reduce the diff for the change. Remove it
and update the remaining tests. NFC modulo reordering of incoming
values.
Clean up after https://github.com/llvm/llvm-project/pull/114292.
DiffChecks will get populated twice when re-trying with runtime checks.
Without clearing it like the regular Checks vector, it will contain some
duplicates and the order the checks are created may not match the order
the checks have been queued when re-trying.
Add a test where diff checks are generated initial and then re-generated
when re-trying with runtime checks.
At the moment, the order doesn't match the order they are created in, as
the DiffChecks field in LAI isn't cleared as other fields holding
runtime checks.
SCEV simplifying the subtraction may result in redundant compares that
are all OR'd together. Keep track of the generated operands in
SeenCompares, with the key being the pair of operands for the compare.
If we alrady generated the same compare previously, skip it.
Instead of expanding the src/sink SCEV expressions and emitting an IR
sub to compute the difference, the subtraction can be directly be
performed by ScalarEvolution. This allows the subtraction to be
simplified by SCEV, which in turn can reduced the number of redundant
runtime check instructions generated.
It also allows to generate checks that are invariant w.r.t. an outer
loop, if he inner loop AddRecs have the same outer loop AddRec as start.