[PATCH] D35579: [SimplifyCFG] Generate lookup tables based on a function attribute

[Chad Rosier via Phabricator via llvm-commits]

mcrosier added a comment.

In https://reviews.llvm.org/D35579#814575, @sgundapa wrote:

> For backends with "tightly coupled memory", in scenarios where the data is far away from text pays a good amount of penalty in terms of latency.
>  Hexagon is one such backend. The tables (both lookup and jump) which are being generated are treated as globals with internal linkage and by default
>  will be placed in read only data.
>
> Interestingly when programmers specify the command line flag "-fno-jump-tables", they assume there is no data that goes in to other sections.
>  In case of llvm, the attribute "no-jump-tables" has no effect on simplifyCFG which generates the lookup table. This leads me to introduce "no-lookup-tables"


It looks like TargetTransformInfo already has a hook, shouldBuildLookupTables(), for disabling this optimization.  Why not just set that to false for Hexagon?


https://reviews.llvm.org/D35579