Talk:Static single-assignment form

mistake

Currently the main page says "if the node A defines a certain variable, then that definition and that definition alone will reach every node A dominates", but this is clearly untrue. The variable can be redefined in other nodes that A dominates. For instance:

 x = 0;
 if(foo())
   bar()
 else
   baz()
 x = 6;
 biz();

The entire code there is dominated by the initial block with x=0 (assuming no non-local control flow out of one of the functions), but the definition of x=0 does not reach biz().

I plan on correcting this once I decide how it should be worded.

arrays and structs

Arrays and structs require special treatment that ought to be described. Loisel 09:53, 22 Apr 2005 (UTC)

Sure. I don't know much about this currently, if you'd like to add it. I'd suggest a separate section, to avoid overwhelming the novice. Deco 16:44, 22 Apr 2005 (UTC)

lwn

There is an explaination of tree SSA in gcc at linux weekly news.

can we have an example involving a loop

I think i can see how this would apply to loops but i'm not sure enough to write an example. Plugwash 23:00, 2 May 2005 (UTC)[reply]

That's a good idea. It does make things a little more interesting. Will look at this when I have time, if no one else does first. Deco 05:14, 3 May 2005 (UTC)[reply]

Summer 2004

Please change summer 2004 (in GCC description) to a correct month --200.178.63.180 05:53, 8 May 2005 (UTC)[reply]

Removed from mains article in SSA Extensions

Is it necessary to enumerate all known SSA extensions? Should each extension have a separate page? What about gated single assignment form, which is probably the most popular SSA extension?

I don't believe we're likely any time soon to have enough material to justify separate pages on each form. Let's keep it all here until one becomes too large. I'm not sure which SSA form is most popular, but I'd hazard a guess of "ordinary" SSA. Deco 02:05, 7 Jun 2005 (UTC)

SSA and AST

The article says SSA is not suitable for tree representations. I can see where this is can be true, but I can also come up with tree representations where it could work (I think). More importantly, GCC now implements a kind of tree-ssa. Anyone care to elaborate on that?? Madhu 03:59, 19 February 2006 (UTC)[reply]

It's more accurate to say that SSA is normally used with linear intermediate representations, not tree-based IRs, but there's no reason it can't be used with tree-based IR as long as reaching definitions are clear. I'll just remove the statement you noted.

As for Tree-SSA, just based on my initial impression it still uses a 3-address (linear) format, but each individual instruction is represented using a tree, for backward compatibility with GCC's tree IR. Deco 06:29, 19 February 2006 (UTC)[reply]

"Φ function" verses "Φ-function"

The literature (e.g. the classic Cryton et al paper, Andrew Appel's books, most papers I have read) use a hyphen between "Φ" and "function". Why is this not followed here? Is it the case that the original authors made a mistake and most literature follows them, either out of respect or ignorance? I don't think that you could say that "Φ" is used as an adjective, so it seems to me that a hyphen is indicated. However, I'm far from confident about this. I'd like to know definitively the correct way to write this term, and I believe that Wikipedia should be a guide in this respect. --Mike Van Emmerik 23:03, 5 August 2006 (UTC)[reply]

We should probably follow what the literature says. Regarding its English correctness, see hyphen. I would regard this as a "noun noun" phrase, which generally is not hyphenated (e.g., ice cream, department store manager), but again I wouldn't contradict the literature. Deco 01:41, 6 August 2006 (UTC)[reply]