How to debug ssa optimizer

[Richard Kenner]

    Hmm?  They're both compatible, v_386 is pointing to the first element of
    version_string.

Yes, but "&version_string" is a shorthand for
	<ADDR_EXPR <VAR_DECL version_string>>
and that has a type of an ARRAY_TYPE.  So what's happening later is
that we have a MODIFY_EXPR whose LHS is a char and whose RHS is an 
ARRAY_TYPE.

I think I'm approaching where it's happening in GDB ...

    Unfortunately, statements have no UIDs in GIMPLE.  You can do indirect
    things like setting a breakpoint at the basic block number and then step
    until you reach the statement.  Adding UIDs to GIMPLE statements would
    be a fine addition for debugging.

Perhaps we can resurrect TREE_COMPLEXITY.  ;-)