Hi Chris,
> // Non-bitfield aggregate value.
> - Emit(TREE_OPERAND(exp, 1), LV.Ptr);
> - if (DestLoc)
> + if (DestLoc) {
> + Emit(TREE_OPERAND(exp, 1), LV.Ptr);
> EmitAggregateCopy(DestLoc, LV.Ptr, TREE_TYPE(exp), isVolatile, false);
why is this ^^^ right? Doesn't a non-null DestLoc mean you are doing something
like: A = (B = C), where DestLoc represents A, and the current MODIFY_EXPR
represents B=C? If so, then the above is bogus: isVolatile says whether writes
to B are volatile, not writes to A: if isVolatile is true, then you are doing
a volatile write to A, which may or may not need it, and a non-volatile write
to B when a volatile write is needed!
> + } else if (!isVolatile) {
> + Emit(TREE_OPERAND(exp, 1), LV.Ptr);
> + } else {
> + // Need to do a volatile store into TREE_OPERAND(exp, 1). To do this,
> we
> + // emit it into a temporary memory location, them do a volatile copy
> into
them -> then
> + // the real destination. This is probably suboptimal in some cases,
> but
> + // it gets the volatile memory access right. It would be better if the
> + // destloc pointer of 'Emit' had a flag that indicated it should be
> + // volatile.
> + Value *Tmp =
> CreateTemporary(ConvertType(TREE_TYPE(TREE_OPERAND(exp,1))));
> + Emit(TREE_OPERAND(exp, 1), Tmp);
> + EmitAggregateCopy(LV.Ptr, Tmp, TREE_TYPE(TREE_OPERAND(exp,1)),
> + isVolatile, false);
> + }
> return 0;
> }
Ciao,
Duncan.
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