RenameIndependentSubregs: Fix iterator problem

Fixes bug 33597.

Use of substituteRegister in the tied operand case messes
up the register use iterator, causing some uses to be left
unprocessed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306333 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed