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Re: The "980505-1.c" bug (The Story Continued)
- To: Carlo Wood <carlo at runaway dot xs4all dot nl>
- Subject: Re: The "980505-1.c" bug (The Story Continued)
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Fri, 10 Jul 1998 23:55:33 -0600
- cc: egcs at cygnus dot com
- Reply-To: law at cygnus dot com
In message <199807110128.DAA16618@jolan.ppro>you write:
> The "libcall" case is just one of the many cases this can happen :/.
> I think therefore that Jeffs patch (cvs diff -c3p -r1.39 -r1.40 cse.c)
> is not sufficient for the whole family of bugs of this type.
>
> reg_in_table[i] = reg_tick[i] occurs at one single line in the code.
> When I put the following in front of it:
>
> if (reg_tick[i] == 0)
> abort();
>
> then, with Jeffs patch added, "make check-gcc" fails for THOUSANDS of
> test cases! In other words: It is VERY commmon that an expression with
> an uninitialized register is validated as having a meaningful value :/.
Nope. See my previous message. It is common for local CSE to not see an
initializing instruction for a register. This is not a problem.
jeff