DAGCombine should not aggressively fold SEXT(VSETCC(...)) into a wider VSETCC without first checking the target's vector boolean contents.
This exposed an issue with PowerPC AltiVec where it appears it was setting the wrong vector boolean contents.  The included change
fixes the PowerPC tests, and was OK'd by Hal.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180129 91177308-0d34-0410-b5e6-96231b3b80d8
[mips] Compare splat value with element size instead of calling isUIntN.

No intended changes in functionality.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180130 91177308-0d34-0410-b5e6-96231b3b80d8
Change commentary for PowerPC Boolean vector contents.

No functional change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180131 91177308-0d34-0410-b5e6-96231b3b80d8