[llvm-commits] [llvm] r142530 - in /llvm/trunk: lib/Target/ARM/ARMISelLowering.cpp test/CodeGen/ARM/2011-10-18-DisableMovtSize.ll

[Rafael Ávila de Espíndola]

> I think we just want another attribute, just like OptimizeForSize but
> the Oz variant.  Maybe OptimizeForSizeHarder ;-)

Do you have an example or two of things that should go in 
OptimizeForSize or OptimizeForSizeHarder?

I find the current description of -Os a bit hard to understand. If it 
introduces no performance regression, why it is not in -O2?

A quick look a the code suggest that we could says that -Os is supposed 
to limit passes that can introduce code bloat like inlining or tail 
duplication. It should not be used for introducing tradeoffs in codegen. 
In summary, "don't bloat the code to make it faster".

The decisions for using slower but smaller code would go to -Oz.

Does this sound like a correct description?

> -Chris

Cheers,
Rafael