count-one-bits: compilation failure with HP-UX cc

[Bruno Haible]

The count-one-bits module fails to compile with HP-UX 11 "cc -Ae":

cc -Ae -O -DHAVE_CONFIG_H -I.  -I. -I.  -I.. -I./..  -I../gllib -I./../gllib  
-I/nfs/visu/telecom/users/haible/gnu/arch/hp9800/include  -g -c 
test-count-one-bits.c
cc: "../gllib/count-one-bits.h", line 56: error 1511: Bit-field size must be a 
constant.
cc: "../gllib/count-one-bits.h", line 56: error 1613: Zero-sized struct.
cc: "../gllib/count-one-bits.h", line 56: warning 504: The sizeof operator 
applied to a zero-sized object.
cc: "../gllib/count-one-bits.h", line 63: error 1511: Bit-field size must be a 
constant.
cc: "../gllib/count-one-bits.h", line 63: error 1613: Zero-sized struct.
cc: "../gllib/count-one-bits.h", line 63: warning 504: The sizeof operator 
applied to a zero-sized object.

Very strange compiler bug:

  $ cat foo.c
  typedef struct { unsigned int x: ((1U >> 31 <= 3) * 2 - 1); } foo;
  $ cc -Ae -c foo.c
  cc: "foo.c", line 1: error 1511: Bit-field size must be a constant.
  cc: "foo.c", line 1: error 1613: Zero-sized struct.

I'm working around it like this:


2008-04-13  Bruno Haible  <address@hidden>

        * lib/count-one-bits.h (COUNT_ONE_BITS): Rewrite verification
        expression, so as to avoid HP-UX 11 cc compiler bug.

--- lib/count-one-bits.h.orig   2008-04-13 19:22:57.000000000 +0200
+++ lib/count-one-bits.h        2008-04-13 19:17:39.000000000 +0200
@@ -1,5 +1,5 @@
 /* count-one-bits.h -- counts the number of 1-bits in a word.
-   Copyright (C) 2007 Free Software Foundation, Inc.
+   Copyright (C) 2007-2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -30,7 +30,7 @@
         return BUILTIN (x);
 #else
 #define COUNT_ONE_BITS(BUILTIN, TYPE)                                       \
-        verify ((TYPE) -1 >> 31 >> 31 <= 3); /* TYPE has at most 64 bits */ \
+        verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 
bits */ \
         int count = count_one_bits_32 (x);                                  \
         if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */          \
           count += count_one_bits_32 (x >> 31 >> 1);                        \