| Issue |
171640
|
| Summary |
[AArch64][SDAG] Canonization of abds? (low level details)
|
| Labels |
backend:AArch64,
llvm:SelectionDAG
|
| Assignees |
|
| Reporter |
natanelh-mobileye
|
As part of the `ISD::ABDS/U` patterns, there are multiple ways to present the condition.
See the following (two functions differing only in the icmp instruction):
codegen diff:
https://godbolt.org/z/an8YM8rfM
correctness of equivalence:
https://alive2.llvm.org/ce/z/Hyubnc
should we canonize `(icmp slt, a, b)` into `(icmp slt, (sub nsw a, b), 0)` when the `sub` node already exists (or the other way)? or just capture it as yet another pattern in SelectionDAG?
(asking before uploading a change)
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