Diego Novillo <[EMAIL PROTECTED]> writes: > > I personally find it kind of baffling to have the same tree code act > > differently in GENERIC and GIMPLE, a la SWITCH_EXPR. It seems to add > > confusion for minimal benefit. If you are suggesting that the single > > tree code GOMP_PARALLEL have different operands in GENERIC and GIMPLE, > > can I suggest that you instead use two different tree coes? > > > That is a fundamental feature of both GENERIC and GIMPLE. GIMPLE > is a non-strict subset of GENERIC. Every program in GIMPLE form > is also in GENERIC form. The reverse, however, is not true.
Well, sure. But it seems to me that there is a difference. PLUS_EXPR always takes two operands and adds them together. Given a PLUS_EXPR, you always where to find the operands, and more or less what they mean. I don't find that confusing, although I agree that the operands themselves may be different in GENERIC and GIMPLE. SWITCH_EXPR is different. Sometimes you use SWITCH_BODY, and sometimes you use SWITCH_LABELS. How do you know which one to use? It depends on whether you have GENERIC or GIMPLE. In particular, this matters for functions like block_may_fallthru, which are called with both GENERIC and GIMPLE. > If we did that we would need different codes for every tree code > (MODIFY_EXPR, PLUS_EXPR, etc). Similarly, we would need > different codes when we move from High-GIMPLE into Low-GIMPLE. > I'm not sure that's worth the effort. From the point of view of > analysis and optimizations the differences between the different > ILs are mostly in the grammar, not their syntax. If I understand what you are saying, I am complaining about the specific cases where the difference is in the syntax. If a tree takes a different set of operands in GENERIC and GIMPLE, or if the operands have significantly different meanings, then I think we should use a different tree code. If the operands are more or less the same, then I think using the same tree code is fine. This is obviously all just my opinion, as somebody who came late to this stuff and is trying to understand it. Ian
