Fix PPC ABI for ByVal structs with vector members

When a structure is passed by value, and that structure contains a vector
member, according to the PPC ABI, the structure will receive enhanced alignment
(so that the vector within the structure will always be aligned).

This should resolve PR16641.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190636 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary TBAA metadata from r190636's test case

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190637 91177308-0d34-0410-b5e6-96231b3b80d8
Remove an unused variable, fixing -Werror build with latest Clang.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190640 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Move fabs/fneg/sel folding logic into PostProcessIsel

This move makes possible to correctly handle multiples instructions
from a single pattern.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190643 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Move code handling literal folding into R600ISelLowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190644 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Move clamp handling code to R600IselLowering.cpp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190645 91177308-0d34-0410-b5e6-96231b3b80d8