On 12/23/2009 02:43 PM, Jie Zhang wrote:
Hi,
We just got a similar problem on Blackfin GCC recently. Let me take the
test code from the bug as an example:
I reduce the test case to a simpler one:
$ cat foo.c
unsigned int
foo (volatile unsigned short *p)
{
return *p;
}
I the tree dump "foo.c.126t.optimized", GCC refused to eliminate D.1256
because the first statement contains a volatile operand:
D.1256 ={v} *p;
return (unsigned int) D.1256;
I'm not familiar with the trees. Is it possible to replace D.1256 and
have something like below?
return (unsigned int) {v} *p;
I experiment a little. It seems {v} will be lost in SSA name replacing
during out of SSA transform. Can anyone pointed me if it's possible to
do the replace but still keep {v}? Or I should find another way to do
that? Or it's wrong to do this optimization?
Thanks,
Jie
