[DAGCombiner] Call ExtendUsesToFormExtLoad in (zext (and (load)))->(and (zextload...

[DAGCombiner] Call ExtendUsesToFormExtLoad in (zext (and (load)))->(and (zextload)) even when the and does not have multiple uses

Same for the sign extend case.

Currently we check for multiple uses on the binop. Then we call ExtendUsesToFormExtLoad to capture SetCCs that use the load. So we only end up finding any setccs when the and has additional uses and the load is used by a setcc. I don't think the and having multiple uses is relevant here. I think we should only be checking for the load having multiple uses.

This changes an NVPTX test because we now find that the load has a second use by a truncate, but ExtendUsesToFormExtLoad only looks at setccs it can extend. All other operations just check isTruncateFree. Maybe we should allow widening of an existing truncate even if its not free?

Differential Revision: https://reviews.llvm.org/D43063

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325289 91177308-0d34-0410-b5e6-96231b3b80d8