[PATCH] D73722: [SCEV] SCEVExpander::isHighCostExpansionHelper(): cost-model plain UDiv

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev accepted this revision.
mkazantsev added a comment.
This revision is now accepted and ready to land.

LGTM



================
Comment at: llvm/test/Transforms/IndVarSimplify/exit_value_test2.ll:24
+; CHECK-NEXT:    [[TMP1:%.*]] = udiv i32 [[TMP0]], 12
+; CHECK-NEXT:    [[TMP2:%.*]] = mul i32 [[TMP1]], 12
 ; CHECK-NEXT:    br label [[WHILE_BODY:%.*]]
----------------
lebedev.ri wrote:
> mkazantsev wrote:
> > Why do we need this change if it starts generating worse code?
> We need this change because the goal of this patchset is to move
> the *entirety* of SCEVExpander::isHighCostExpansionHelper()
> to TTI cost-modelling. Entirety as in everything.
> 
> Also, please do see the patch's description:
> > While that is the case, it is evident this is actually a regression
> > due to the fact that cost-modelling is incomplete - we did not account
> > for the add, mul costs yet. That is being addressed in D73728.
> 
Ok it seems the next patch fixes it back. Thanks. :)


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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D73722/new/

https://reviews.llvm.org/D73722