On Mon, Mar 07, 2005 at 04:59:38PM -0000, Simon Marlow wrote:
The mystery as to why this doesn't affect us on x86 is solved: on x86 we generate slightly different C code, including a dummy function call:
extern void g(void); static void f(void) { R1 = g; dummy(); goto *R1; }
the call to dummy() (which we filter out from the assembly later) is enough to force gcc to emit the assignment to R1. That dummy function call has been there for ever, and the original reason for it has been lost in the mists of time... comments in the source code seemed to indicate that it was probably not necessary any more, so for x86_64 I removed it. It looks like I'll have to reinstate it to work around this bug, though.
gcc 3.3.4 on AMD64 appears to generate correct code when the dummy call is present. Ick. Dave