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From: Graham Stott <graham.stott@btinternet.com>
To: gcc-bugzilla@gcc.gnu.org
Cc: gcc-bugs@gcc.gnu.org
Subject: Re: [Bug middle-end/17036] [3.5 Regression] ICE: (A >> N) & 1 ? (1 << N) : 0 where A of type unsigned int
Date: Sun, 15 Aug 2004 18:05:00 -0000 [thread overview]
Message-ID: <411FA5D7.3030003@btinternet.com> (raw)
In-Reply-To: <20040815170538.25318.qmail@sourceware.org>
pinskia at gcc dot gnu dot org wrote:
> ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-08-15 17:05 -------
> Confirmed
> : Search converges between 2004-06-20-trunk (#469) and 2004-06-22-trunk (#470).
> Reduced to:
> int main( int argc, char **arg )
> {
> int R , N = 4;
> unsigned int A = 2;
> signed int B = 2;
> ((B >> N) & 1) ? 1 : 0;
> ((A >> N) & 1) ? 1 : 0;
> return 0;
> }
>
>
> Looks like someone forgets to check to make sure that the N is really a constant.
>
This patch should fixit but I don't have time to do a full bootstrap and
regression test on the patch.
-------------------------------------------------------------------
Index: fold-const.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/fold-const.c,v
retrieving revision 1.435
diff -c -p -r1.435 fold-const.c
*** fold-const.c 12 Aug 2004 04:01:04 -0000 1.435
--- fold-const.c 15 Aug 2004 17:53:10 -0000
*************** fold (tree expr)
*** 8874,8879 ****
--- 8874,8880 ----
tree tem = TREE_OPERAND (arg0, 0);
STRIP_NOPS (tem);
if (TREE_CODE (tem) == RSHIFT_EXPR
+ && TREE_CODE (TREE_OPERAND (tem, 1)) == INTEGER_CST
&& (unsigned HOST_WIDE_INT) tree_log2 (arg1) ==
TREE_INT_CST_LOW (TREE_OPERAND (tem, 1)))
return fold (build2 (BIT_AND_EXPR, type,
-------------------------------------------------------------------
next prev parent reply other threads:[~2004-08-15 18:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-15 16:55 [Bug c/17036] New: " bommar33 at msu dot edu
2004-08-15 16:57 ` [Bug c/17036] " bommar33 at msu dot edu
2004-08-15 17:05 ` [Bug middle-end/17036] [3.5 Regression] " pinskia at gcc dot gnu dot org
2004-08-15 18:05 ` Graham Stott [this message]
2004-08-15 18:05 ` graham dot stott at btinternet dot com
2004-08-15 18:57 ` bommar33 at msu dot edu
2004-08-16 7:19 ` paolo dot bonzini at polimi dot it
2004-08-17 7:40 ` cvs-commit at gcc dot gnu dot org
2004-08-17 8:19 ` pinskia at gcc dot gnu dot org
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