Add option to limit the maximal number of parallel threads.

Differential Revision: http://reviews.llvm.org/D5581



git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@219004 91177308-0d34-0410-b5e6-96231b3b80d8
Put the parallel context alloca into the function entry block.

  We use lifetime markers to limit the actual life range (similar to clang).

Differential Revision: http://reviews.llvm.org/D5582



git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@219005 91177308-0d34-0410-b5e6-96231b3b80d8