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Re: Deadly optimization bug (all gcc versions!)
- To: veksler at il dot ibm dot com
- Subject: Re: Deadly optimization bug (all gcc versions!)
- From: David Edelsohn <dje at watson dot ibm dot com>
- Date: Mon, 16 Aug 1999 12:41:31 -0400
- Cc: egcs at egcs dot cygnus dot com
>>>>> veksler writes:
veksler> The bug shows itself on gcc-2.7.0 gcc-2.7.2.1, egcs-1.0.1, egcs-1.1.2,
veksler> gcc-2.95.
veksler> On AIX-4.1, Linux-x86 (RH4.2 and RH6.0).
This means that you have seen the bug in both PowerPC and IA-32
code generation? I definitely see it in PowerPC. A whole group of
instructions disappear between flow and combine. Also, -O3 with inlining
seems to produce correct results. Maybe combine is trying some alternate
instructions, failing, and then not properly restoring the instructions?
David