[PATCH] D38952: [ARM] Allow unrolling on multi-block loops.

Sam Parker via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Oct 17 02:58:54 PDT 2017


samparker added inline comments.


================
Comment at: lib/Target/ARM/ARMTargetTransformInfo.cpp:628
+                                            I.value_op_end());
+      Cost += getUserCost(&I, Operands);
     }
----------------
efriedma wrote:
> Would it make sense to break out of this loop early if "Cost" is 12 or more?
No, we still want to allow partial and runtime unrolling and the default thresholds in the unroller work well for loops which the unroller understands. The cost is used to force the unroller to do its thing on small loops that it otherwise wouldn't unroll.


https://reviews.llvm.org/D38952





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