Path: utzoo!mnetor!uunet!husc6!bbn!rochester!cornell!uw-beaver!uw-june!uw-entropy!dataio!bright
From: bright@Data-IO.COM (Walter Bright)
Newsgroups: comp.lang.c++
Subject: Re: C++ releases from AT&T?
Message-ID: <1517@dataio.Data-IO.COM>
Date: 30 Mar 88 18:41:11 GMT
References: <254@piring.cwi.nl>
Reply-To: bright@dataio.UUCP (Walter Bright)
Organization: Data I/O Corporation; Redmond, WA
Lines: 14

In article <254@piring.cwi.nl> guido@cwi.nl (Guido van Rossum) writes:
<I asked about the official status of unreachable code elimination by
<the translator earlier, but didn't get useful replies.
<So, anybody care
<to comment on the question of what happens to code after
<"if (constant-expression-evaluating-to-zero) ..." ?

The code should be deleted in any optimizing compiler. A compiler that
readsanexpression/generatescodeforexpression cannot simply delete it, because
there may be labels in the then-expression.

In my C++ compiler (and my C compiler), any control flow where the compiler
can figure out which branch will always be taken is optimized. I also believe
this is an implementation issue, not a language issue.