PowerPC: CTR shouldn't fire if a TLS call is in the loop
Determining the address of a TLS variable results in a function call in
certain TLS models. This means that a simple ICmpInst might actually
result in invalidating the CTR register.
In such cases, do not attempt to rely on the CTR register for loop
optimization purposes.
This fixes PR22034.
Differential Revision: http://reviews.llvm.org/D6786
This fixes a "Invalid PPC CTR loop" error when compiling parts of libc
for PowerPC-32.
c1ddc1e628