optimization/7782: [3.3 regression] C++ compiler internal error in delete_insn, at cfgrtl.c:139

[Wolfgang Bangerth <bangerth@ticam.utexas.edu>]

The following reply was made to PR optimization/7782; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
To: gcc-gnats@gcc.gnu.org
Cc:  
Subject: optimization/7782: [3.3 regression] C++ compiler internal error in
 delete_insn, at cfgrtl.c:139
Date: Wed, 11 Dec 2002 11:09:57 -0600 (CST)

 OK, here's the first result of the "regression tracking special team" 
 (Craig, Janis, me, maybe Volker): 
 
 The cause for PR 7782 is this patch:
 
 > 2002-01-10  Richard Henderson  <rth@redhat.com>
 >
 >       * cfgrtl.c (delete_insn): Assert insn hasn't been deleted yet.
 >       * reload1.c (delete_output_reload): Zap spill_reg_store.  Take
 >       care not to delete instructions twice.
 
 Here's a testcase:
 -----------------
 // g++ -O -c PR7782.cc
 
 struct A {
    long long x, y;
    void bar () const {
       A a;
       a.y = ~y;
       if ((a.x = -y)) ++a.y;
    }
    void foo (int) const;
 };
 
 void A::foo (int i) const {
    if (i) bar(); if (i) bar();
 }
 ------------------
 
 Here's the error:
 tmp/g> /home/bangerth/tmp/gcc/p/b/gcc/cc1plus -O -quiet PR7782.cc
 PR7782.cc: In member function `void A::foo(int) const':
 PR7782.cc:18: Internal compiler error in delete_insn, at cfgrtl.c:140
 
 
 Richard, I understand that the bug may only have been uncovered by your 
 inserting an assertion, but maybe you can say something about it anyway.
 
 Regards
   Wolfgang
 
 PS: I'm sorry that my first "victim" is someone who has, by reviewing all 
 those patches, helped gcc in such a major way...
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth              email:           bangerth@ticam.utexas.edu
                                www: http://www.ticam.utexas.edu/~bangerth