Remove TargetInstrInfo::copyRegToReg entirely.

Targets must now implement TargetInstrInfo::copyPhysReg instead. There is no
longer a default implementation forwarding to copyRegToReg.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108095 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/WritingAnLLVMBackend.html b/docs/WritingAnLLVMBackend.html
index d909a1a..077dea0 100644
--- a/docs/WritingAnLLVMBackend.html
+++ b/docs/WritingAnLLVMBackend.html
@@ -1310,7 +1310,8 @@
     a direct store to a stack slot, return the register number of the
     destination and the <tt>FrameIndex</tt> of the stack slot.</li>
 
-<li><tt>copyRegToReg</tt> &mdash; Copy values between a pair of registers.</li>
+<li><tt>copyPhysReg</tt> &mdash; Copy values between a pair of physical
+    registers.</li>
 
 <li><tt>storeRegToStackSlot</tt> &mdash; Store a register value to a stack
     slot.</li>