Do a scheduling pass ignoring anti-dependencies to identify candidate registers that should be renamed.

llvm-svn: 85939

Between scheduling regions, correctly maintain anti-dep breaking state so that we don't incorrectly rename registers that span these regions.

llvm-svn: 85537

llvm-svn: 85522

Allow the aggressive anti-dep breaker to process the same region multiple times. This is necessary because new anti-dependencies are exposed when "current" ones are broken.

llvm-svn: 85166

Add aggressive anti-dependence breaker. Currently it is not the default for any target. Enable with -break-anti-dependencies=all.

llvm-svn: 85145