instructions which define each value#) to simplify and improve the coallescer.
In particular, this patch:
1. Implements iterative coallescing.
2. Reverts an unsafe hack from handlePhysRegDef, superceeding it with a
better solution.
3. Implements PR865, "coallescing" away the second copy in code like:
A = B
...
B = A
This also includes changes to symbolically print registers in intervals
when possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29862 91177308-0d34-0410-b5e6-96231b3b80d8
f7da2c7b0c