[PATCH] gold, libLTO: Add new flags to support bit set lowering.

[Manman Ren]

Hi Peter,

This will change the default behavior of LTO API.
We used to run LowerBitSetsPass when OptLevel is not zero. But now it is controlled by the flag “lowerbitsets” in tools/lto/lto.cpp, where the default value is false.

Also with the patch, we run CFGSimplificationPass one more time when OptLevel is not zero and LowerBitSets is true.

Thanks,
Manman

> On Mar 17, 2015, at 4:03 PM, Rafael Ávila de Espíndola <rafael.espindola at gmail.com> wrote:
> 
> ================
> Comment at: lib/Transforms/IPO/PassManagerBuilder.cpp:530
> @@ +529,3 @@
> +    // Clean up after the bit set lowering pass.
> +    PM.add(createCFGSimplificationPass());
> +
> ----------------
> Should these still be enabled at -O0?
> 
> ================
> Comment at: tools/gold/gold-plugin.cpp:98
> @@ -97,1 +97,3 @@
>   static std::string mcpu;
> +  static bool disable_opt = false;
> +  static bool lowerbitsets = false;
> ----------------
> DisableOpt.
> LowerBitSets.
> 
> http://reviews.llvm.org/D8401
> 
> EMAIL PREFERENCES
>  http://reviews.llvm.org/settings/panel/emailpreferences/
> 
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits