------- Comment #16 from rask at gcc dot gnu dot org 2007-11-23 20:43 -------
(In reply to comment #
> I think the bug can be closed as fixed now.
I'm not so convinced. This part
> leal (%ecx,%edx), %esi
> movl %esi, %edx
> movl 4(%esp), %esi
should have been
addl %ecx, %edx
movl 4(%esp), %esi
and using %esi instead of a stack slot doesn't fix the problem. Compare with
what we started with (comment #0):
> movl %edx, 4(%esp) hi+a0*b1 ! Could be simplified
> addl %ecx, 4(%esp) hi+a0*b1+a1*b0 ! to a single insn:
> movl 4(%esp), %edx ! addl %ecx, $edx
The problem hasn't been fixed until we get that "addl %ecx, %edx" instruction.
One more example:
movl 16(%esp), %eax -> movl 16(%esp), %esi
movl 20(%esp), %esi -> movl 20(%esp), %eax
imull %ebx, %ecx
imull %esi, %eax -> imull %eax, %esi
addl %eax, %ecx -> addl %esi, %ecx
movl %esi, %eax -> -
mull %ebx
This is exactly what a register allocator is supposed to figure out: Register
allocation.
--
rask at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|FIXED |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=6585
