ARM constant folding bug?

[Jonathan S. Shapiro]

On Fri, 2007-08-03 at 17:24 +0100, Dave Korn wrote:

> > I am not surprised that there is different behavior for different
> > targets, but I am very surprised that *this* behavior is different. This
> > optimization ought to be happening in the mid-end, and it ought to be
> > entirely machine independent.
> 
>   I'm a bit surprised too.  But it occurs to me that the ARM, unlike the i386
> and m68k, is bi-endian.  Perhaps you can't actually know which mode it's
> running in at compile time and /have/ to test it at runtime?

That seems counter-intuitive, since a given compiler instance is
configured for a target with a particular endian-ness. Even if the
compiler can evade knowledge, the assembler surely must know. Of course,
I am not running the assembler here.

In any case, an interesting hypothesis. Would also explain some code
pessimization issues for ARM targets more generally.

shap