[mips][msa] Fix corner case for integer constant splats with undef values.

lowerBUILD_VECTOR() was treating integer constant splats as being legal
regardless of whether they had undef values. This caused instruction
selection failures when the undefs were legalized to zero, making the
constant non-splat.

Fixed this by requiring HasAnyUndef to be false for a integer constant
splat to be legal. If it is true, a new node is generated with the undefs
replaced with the necessary values to remain a splat.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195455 91177308-0d34-0410-b5e6-96231b3b80d8
Fix typo in a comment added in r195455.

Credit to Matheus Almeida for spotting it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195456 91177308-0d34-0410-b5e6-96231b3b80d8
ARM: use CHECK-LABEL on a test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195457 91177308-0d34-0410-b5e6-96231b3b80d8