These tests rely on SCEV looking recognizing an "or" with no common
bits as an "add". Add the disjoint flag to relevant or instructions
in preparation for switching SCEV to use the flag instead of the
ValueTracking query. The IR with disjoint flag matches what
InstCombine would produce.
Before D135808, There would be endless loop interchange posibility (no
proper priority was there in profitability check. Any profitable check
may leads to loop-interchange). With this patch, there is no endless
interchange (priority in profitable check is defined. Order of decision
is 'Cache cost' check, 'InstrOrderCost', 'Vectorization'). Corrected the
dependency checking inside isProfitableForVectorization(), corrected the
checking of bad order loops in isProfitablePerInstrOrderCost().
Reviewed By: Meinersbur, bmahjour, #loopoptwg
Differential Revision: https://reviews.llvm.org/D135808
This is a bugfix patch that resolves the following two bugs in loop interchange:
1. PR57148 which is an assertion error due to of loss of LCSSA form after interchange,
as referred to test1() in pr57148.ll.
2. Use before def for the outermost loop induction variables after interchange,
as referred to test2() in pr57148.ll.
The fix in this patch is that:
1. In cases where the LCSSA form is not maintained after interchange, we update the IR
to the LCSSA form again.
2. We split the phi nodes in the inner loop header into a separate basic block to avoid
the situation where use of the outer indvar appears before its def after interchange.
Previously we already did this for innermost loops, now we do it for non-innermost
loops (e.g., middle loops) as well.
Reviewed By: bmahjour, Meinersbur, #loopoptwg
Differential Revision: https://reviews.llvm.org/D132055
