LWenH wrote: > > Shouldn't we forget about L1 when we get to L2? > > I agree with we should forget about L1 when we get to L2. The semantic of > `Copies[Unit].DefRegs` should be Registers defined by `Unit` in COPY > instructions, we want to keep this invariant during tracking. I think it's > appropriate to keep this property during `trackCopy`. After L2, `Copies[<r9's > units>].DefRegs` still containing `r0` is violating this property.
Address @qcolombet and @bzEq 's comments, after more carefully reconsideration, I think we could always do this DefRegs record elimination when we inivoke the **clobberRegister** routine. When we clobber a single register(Def), the semantic of Src's **DefRegs** to contain Def is no longer effectual, because the **DefRegs** is always used in **findCopyDefViaUnit** during the **BackwardCopyPropagateBlock** function. After we clobbering a single register, the Src is no longer propagatable either. In other word, we don't need to keep this record in the tracker after we clobbering a **Def** register. https://github.com/llvm/llvm-project/pull/70778 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
