PMBuilder: Expose an option to disable tail calls

Adds API to allow frontends to disable tail calls in PassManagerBuilder.

<rdar://problem/16050591>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206542 91177308-0d34-0410-b5e6-96231b3b80d8
Fix example for VS2012.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206544 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Match sign_extend_inreg to s_sext_i32_i8 and s_sext_i32_i16

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206547 91177308-0d34-0410-b5e6-96231b3b80d8