the code being generated does not require an executable stack.
Also, add target-specific code to make use of this on Linux
on x86.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50634 91177308-0d34-0410-b5e6-96231b3b80d8
If it cannot be expanded, it will keep the old behaviour and try to shrink the constant.
Part of enhancement for PR2191.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49280 91177308-0d34-0410-b5e6-96231b3b80d8