About the 2nd instruction scheduling

[Hsin-Hsien Wu]

Hello,
The gccint manual says:
The second Haifa scheduling pass, for targets that can multiple issue, sets
the mode of an insn to TImode when it is believed that the instruction
begins an issue group. That is, when the instruction cannot issue
simultaneously with the previous. This may be relied on by later passes, in
particular machine-dependent reorg. 
 
What if the haifa scheduler doesn't set an insn to TImode or to VOIDmode?
 

Thanks.
 
Mike