http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40635

--- Comment #5 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to philipp from comment #4)
> I have this or a very similar problem with debian amd64 4:4.8.2-1:
> 
> main.c: In function ‘main’:
> main.c:1231:23: error: ‘rv’ may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
>   return (rv_main >= 0 && rv_main < 0x70) ? rv_main : 1;

Can you attach a small, preprocessed testcase? See
http://gcc.gnu.org/bugs/minimize.html
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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/59557] New: [4.8/4.9 Regression]
Date: Thu, 19 Dec 2013 10:39:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idY557

            Bug ID: 59557
           Summary: [4.8/4.9 Regression]
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org

Created attachment 31479
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id1479&actioníit
testcase

A libstdc++ change between r202388 and the 4.8.2 release broke Eigen.
Preprocessing the attached testcase with 4.8.2 and then compiling with -O0
gives

> ./a.out
Brute force distance = 0.00428018, calls = 10000
Segmentation fault

while preprocessing with 4.8.1 gets the correct

> ./a.out
Brute force distance = 0.00428018, calls = 10000
BVH distance         = 0.00428018, calls = 756