[PATCH] D151848: [X86, Peephole] Enable FoldImmediate for X86

Wed May 31 20:52:29 PDT 2023

Carrot added inline comments.

================
Comment at: llvm/lib/CodeGen/PeepholeOptimizer.cpp:1391
+      // FoldImmediate can delete ImmDefMI if MI was its only user. If ImmDefMI
+      // is not deleted, and we happenly get a same MI, we can delete MI and
+      // replace its users.
----------------
craig.topper wrote:
> Carrot wrote:
> > craig.topper wrote:
> > > happenly?
> > The case I encountered is
> > ```
> >      %1 = MOV32ri   4
> >      %2 = COPY %1
> >       // other uses of %1
> >      ...
> > ```
> > After FoldImmediate it becomes
> > ```
> >     %1 = MOV32ri 4
> >     %2 = MOV32ri 4
> > ```
> > Becuase %1 has multiple uses, so it can't be deleted by FoldImmediate. These two instructions are identical now, so we can replace the uses of %2 by %1, and delete the definition of %2.
> I was questioning whether "happenly" is a real word.
Sorry for my poor English. It should be happened.

Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151848/new/

https://reviews.llvm.org/D151848