Use AA in LoadCombine

LoadCombine can be smarter about aborting when a writing instruction is
encountered, instead of aborting upon encountering any writing instruction, use
an AliasSetTracker, and only abort when encountering some write that might
alias with the loads that could potentially be combined.

This was originally motivated by comments made (and a test case provided) by
David Majnemer in response to PR21448. It turned out that LoadCombine was not
responsible for that PR, but LoadCombine should also be improved so that
unrelated stores (and @llvm.assume) don't interrupt load combining.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221203 91177308-0d34-0410-b5e6-96231b3b80d8
Rename variables to conform to llvm coding standards.

Differential Revision: http://reviews.llvm.org/D6062


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221204 91177308-0d34-0410-b5e6-96231b3b80d8
Change logic in StackMaps::recordStackMapOpers to use the isInt<32>
predicate instead of bitwise operations.

This is not a functional change.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221209 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] Reverting 220584 to address ASAN errors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221210 91177308-0d34-0410-b5e6-96231b3b80d8