Add fortified (__*_chk) library functions to TLI (NFC)

One of them (__memcpy_chk) was already there, the others were checked
by comparing function names.
Note that the fortified libfuncs are now part of TLI, but are always
available, because they aren't generated, only optimized into the
non-checking versions.

Differential Revision: http://reviews.llvm.org/D6179


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221817 91177308-0d34-0410-b5e6-96231b3b80d8
Expose the number of Newton-Raphson iterations applied to the hardware's reciprocal estimate as a parameter (x86).

This is a follow-on to r221706 and r221731 and discussed in more detail in PR21385.

This patch also loosens the testcase checking for btver2. We know that the "1.0" will be loaded, but
we can't tell exactly when, so replace the CHECK-NEXT specifiers with plain CHECKs. The CHECK-NEXT
sequence relied on a quirk of post-RA-scheduling that may change independently of anything in these tests.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221819 91177308-0d34-0410-b5e6-96231b3b80d8