problem in global allocation

[Heiko Panther]

I'm hunting a bug in the or32-gcc port, which I'm taking to Mac OS X. 
The or32 is a 32 bit machine (www.opencores.org), and the gcc compiler 
works fine for i86-linux.

In global.c, find_reg:1056 ff, something bad happens. find_reg is 
processing a request for a DI, and it finds r31 suitable. I assume it is 
not suitable, since there is no r32 to hold the second part of the DI.

I believe the main problem is that TEST_HARD_REG_BIT(used, 32) returns 0 
and thus r32 is believed to be available. This happens because "used" of 
type HARD_REG_SET is a 32 bit integer, which I assume is legal.

If I am not mistaken, this would generally mean that find_reg() might 
yield errors for n-bit targets if the host HARD_REG_SET is not more than 
n bits wide. The reason that the x86 port works could be that the 
HARD_REG_SET is 64 bit wide there for some reason, but I did not check 
that. Did I make a mistake?

My quickly hacked workaround

1066:		    &&  TEST_HARD_REG_BIT (~used, j));

seems to do the trick.


Heiko Panther