Re: Pb with clearing const_tiny_rtx in clear_const_double_mem

[Richard Henderson <rth at redhat dot com>]

On Fri, Aug 24, 2001 at 03:53:03PM +0200, Olivier Hainque wrote:
>        float f1 = 1.0;
> 
>        void bar (void)
> 	 {
> 	 }
> 
>        float f2 = 1.0;

Ug.

> I'm unclear as to what the initial problem was.

The nested function wouldn't use the canonical values, which means all of
the checks for CONST0_RTX etc fail, which causes instructions to not match
in the alpha backend, as well as lots o missed optimizations.

One way to solve this problem is to swap out these tiny_rtx's in the nested
context so that they are not shared, but we still match CONST0_RTX.  Care
should be taken so that the original functions are restored by the time we
get to integrate.c.

A larger issue is that it is damned stupid to not share constants between
functions on machines that just dump constants in .rodata and don't have
in-function constant pools.  That's a somewhat large cleanup though.



r~