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From: "ahanins at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug other/60336] New: va_start corrupts 6-th argument in case of empty type used before the format string
Date: Tue, 25 Feb 2014 09:36:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60336

            Bug ID: 60336
           Summary: va_start corrupts 6-th argument in case of empty type
                    used before the format string
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ahanins at gmail dot com

Created attachment 32208
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32208&action=edit
va_list corruption simple example

The code in attachment (for convenience see here
http://coliru.stacked-crooked.com/a/14319753d1667629) prints garbage instead of
6-th argument if Dummy struct is empty. Adding some member to this struct
"fixes" the problem. Not sure, whether problem is in Gcc code generation or
libc, but probably related to ABI.

Tested on Ubuntu 13.04 64bit.