[PATCH] D114361: [MachineCSE] Add an option to enable global CSE

[ChenZheng via Phabricator via llvm-commits]

shchenz added inline comments.


================
Comment at: llvm/lib/CodeGen/MachineCSE.cpp:440
+      TII->enableAggressiveMachineCSE(*MI->getMF()))
+    return true;
+
----------------
If the register pressure is increased, doing more CSEs may introduce register spill/reload and thus it will generate worse code even for optimization for size?


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Comment at: llvm/lib/CodeGen/MachineCSE.cpp:468
     if (CSBB != BB && !CSBB->isSuccessor(BB))
       return false;
   }
----------------
Can we estimate the register pressure here to do a more aggressive CSE? If so, we should not limit this only for "optimization for size".


Repository:
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  https://reviews.llvm.org/D114361/new/

https://reviews.llvm.org/D114361