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From: "hp at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/45051]  New: [4.6 Regression]: gcc.c-torture/execute/builtins/abs-2.c and abs-3.c due to "track subwords of DImode allocnos"
Date: Sat, 24 Jul 2010 02:43:00 -0000	[thread overview]
Message-ID: <bug-45051-507@http.gcc.gnu.org/bugzilla/> (raw)

With revision 162417 this test passed.
>From revision 162418 and on, these tests (or "this test" as abs-3.c is
effectively the same as abs-2.c) has failed as follows:
Running
/tmp/badabs/gcc/gcc/testsuite/gcc.c-torture/execute/builtins/builtins.exp ...
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -O2 
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -O3
-fomit-frame-pointer 
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -O3 -g 
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -Os 
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -O2 -flto 
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -O2 -fwhopr 
FAIL: gcc.c-torture/execute/builtins/abs-3.c execution,  -O2 
FAIL: gcc.c-torture/execute/builtins/abs-3.c execution,  -O3
-fomit-frame-pointer 
FAIL: gcc.c-torture/execute/builtins/abs-3.c execution,  -O3 -g 
FAIL: gcc.c-torture/execute/builtins/abs-3.c execution,  -Os 
FAIL: gcc.c-torture/execute/builtins/abs-3.c execution,  -O2 -flto 
FAIL: gcc.c-torture/execute/builtins/abs-3.c execution,  -O2 -fwhopr 

With the message in the logfile being:
...
PASS: gcc.c-torture/execute/builtins/abs-2.c compilation,  -O2 
program stopped with signal 6.
FAIL: gcc.c-torture/execute/builtins/abs-2.c execution,  -O2 
...
(i.e. abort being called)

Author of patch in suspect revision range CC:ed.

At a glance, the code change causes a register containing 0 to be used as
containing 0xffffffff for the low-part of 9223372036854775807LL ((1<<63)-1),
i.e. a mis-tracking of a DImode subreg.

I'll attach a smaller test-case and an assembly diff pointing out the wrong
code.


-- 
           Summary: [4.6 Regression]: gcc.c-torture/execute/builtins/abs-2.c
                    and abs-3.c due to "track subwords of DImode allocnos"
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hp at gcc dot gnu dot org
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: cris-axis-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45051


             reply	other threads:[~2010-07-24  2:43 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-24  2:43 hp at gcc dot gnu dot org [this message]
2010-07-24  2:46 ` [Bug rtl-optimization/45051] " hp at gcc dot gnu dot org
2010-07-24  2:51 ` hp at gcc dot gnu dot org
2010-07-24  3:03 ` hp at gcc dot gnu dot org
2010-07-27  9:35 ` bernds at gcc dot gnu dot org
2010-07-27 21:49 ` bernds at gcc dot gnu dot org
2010-09-21 21:26 ` hp at gcc dot gnu dot org

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