This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
Re: [Bug middle-end/17036] [3.5 Regression] ICE: (A >> N) & 1 ? (1<< N) : 0 where A of type unsigned int
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,
-------------------------------------------------------------------