Option parsing: allow aliases in groups

Option aliases in option groups were previously disallowed by an assert.
As far as I can tell, there was no technical reason for this, and I would
like to be able to put cl.exe compatible options in their own group for Clang,
so let's change the assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186838 91177308-0d34-0410-b5e6-96231b3b80d8
[NVPTX] Remove unused prototypes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186844 91177308-0d34-0410-b5e6-96231b3b80d8
Fix an obvious typo in the loop vectorizer where the cost model uses the wrong variable. The variable BlockCost is ignored.
We don't have tests for the effect of if-conversion loops because it requires a big test (that includes if-converted loops) and it is difficult to find and balance a loop to do the right thing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186845 91177308-0d34-0410-b5e6-96231b3b80d8
MC: mayAffectControlFlow() handling for variadic instructions.

Variadic MC instructions don't note whether the variable operands
are uses or defs, so mayAffectControlFlow() must conservatively
assume they are defs and return true if the PC is in the operand
list.

rdar://14488628

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186846 91177308-0d34-0410-b5e6-96231b3b80d8