[PATCH] D106408: Allow rematerialization of virtual reg uses

Thu Jul 22 10:36:22 PDT 2021

rampitec added inline comments.

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Comment at: llvm/test/CodeGen/X86/licm-regpressure.ll:4
 ; correctly. More details: llvm.org/PR23143
-; XFAIL: *
+; It however passes because leaq is rematerialized instead of spilling.

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jrtc27 wrote:
> RKSimon wrote:
> > Add checks for the lea?
> Or fix the test so it still demonstrates the bug, otherwise this file no longer serves much of a purpose...
The question is: should LICM really check register pressure if we can rely on rematerialization instead? I have started this with a very similar situation in AMDGPU, LICM was hoisting instructions out of the loop and we end up spilling in the loop. A proper rematerialization fixes this without burdening the LICM. I.e. this change shall probably fix the bug itself.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D106408/new/

https://reviews.llvm.org/D106408