[Bug tree-optimization/30016] [4.0/4.1/4.2/4.3 Regression] internal compiler error: in convert_move, at expr.c:362

["pinskia at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #4 from pinskia at gmail dot com  2006-11-30 18:10 -------
Subject: Re:  [4.0/4.1/4.2/4.3 Regression]
        internal compiler error: in convert_move, at expr.c:362

On Thu, 2006-11-30 at 15:55 +0000, dimock at csail dot mit dot edu
wrote:

> 
> (2a) [portability and performance] The standard way of handling the vector
> extensions in gcc is to make a union of the vector and an array of the same
> size so that the vector can be loaded or unloaded without making use of
> machine-specific (non-portable) intrinsics or builtins.  I noticed that in my
> machine-generated code which used unions everywhere, that gcc was able to
> better optimize code if I took out unions where they were not needed (removing
> unused unions produced different .s files on -mcpu=G4 on a PowerPC, and the
> code with unions removed ran faster.  Performance not checked on pentium/SSE
> since my real target is PPE/SPE.) 

The best portability (and better for performance) way is to make a
temporary variable.  Though unions are not that good for performance.
For SPU, you can use spu_extract/spu_insert to get better performance.

Thanks,
Andrew Pinski
a SPU maintainer (and a Cell guy in gneral)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30016