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From: butcher@g.gp.cs.cmu.edu (Lawrence Butcher)
Newsgroups: gnu.gcc.bug
Subject: constant folding bug
Message-ID: <4973@pt.cs.cmu.edu>
Date: 11 May 89 06:26:03 GMT
Distribution: usa
Organization: Carnegie-Mellon University, CS/RI
Lines: 52


gcc 1.35 on a 60820 sun running sun unix 3.5.

gcc seems to constant fold differently than several other c compilers in
this funny case.  I can sort of see it either way.  If constants are
considered ints unless otherwise specified, gcc gets this wrong.

main()
{
    if (0xFFFFF000 < 0x00000FFF)	/* If 2's comp, -256 < 255 */
	printf ("(no type)0xFFFFF000 < (no type)0x00000FFF\n");
    else
	printf ("(no type)0xFFFFF000 >= (no type)0x00000FFF\n");

    if (0xFFFFF000L < 0x00000FFFL)	/* If 2's comp, -256 < 255 */
	printf ("0xFFFFF000L < 0x00000FFFL\n");
    else
	printf ("0xFFFFF000L >= 0x00000FFFL\n");

    if ((short)0xFFFFF000 < (short)0x00000FFF)
	printf ("(short)0xFFFFF000 < (short)0x00000FFF\n");
    else
	printf ("(short)0xFFFFF000 >= (short)0x00000FFF\n");

    if ((unsigned)0xFFFFF000 < (unsigned)0x00000FFF)
	printf ("(unsigned)0xFFFFF000 < (unsigned)0x00000FFF\n");
    else
	printf ("(unsigned)0xFFFFF000 >= (unsigned)0x00000FFF\n");

    if ((signed)0xFFFFF000 < (signed)0x00000FFF)
	printf ("(signed)0xFFFFF000 < (signed)0x00000FFF\n");
    else
	printf ("(signed)0xFFFFF000 >= (signed)0x00000FFF\n");

    if ((int)0xFFFFF000 < (int)0x00000FFF)
	printf ("(int)0xFFFFF000 < (int)0x00000FFF\n");
    else
	printf ("(int)0xFFFFF000 >= (int)0x00000FFF\n");

    if ((long)0xFFFFF000 < (long)0x00000FFF)
	printf ("(long)0xFFFFF000 < (long)0x00000FFF\n");
}

results are:

(no type)0xFFFFF000 >= (no type)0x00000FFF     // which I do not expect
0xFFFFF000L >= 0x00000FFFL                     // likewise seems wrong
(short)0xFFFFF000 < (short)0x00000FFF
(unsigned)0xFFFFF000 >= (unsigned)0x00000FFF
(signed)0xFFFFF000 < (signed)0x00000FFF
(int)0xFFFFF000 < (int)0x00000FFF
(long)0xFFFFF000 < (long)0x00000FFF
--