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Re: undefined behavior if sizeof(mp_limb_t)>sizeof(long)


On Mar 13, 2003, Alexandre Oliva <aoliva at redhat dot com> wrote:

> On Mar 10, 2003, Roland McGrath <roland at redhat dot com> wrote:
>>> This is one I had missed in the mips64-linux port I posted two months
>>> ago, still awaiting review.  Is there any interest in my extracting
>>> the similar bits from that patch and submitting them separately?

>> Yes, please do.

> Here they are.  Ok to install?

Roland asked me to take out the (C) removals (I thought they were
deprecated, but I can't find any official statement to support this
recollection), and to add dates to the ChangeLogs instead of the more
neutral `from' (contrary to every advice I've ever heard about posting
ChangeLog entries :-).  This just proves how much of a non-glibc
person I am, I suppose :-)

Index: ChangeLog
2003-03-13  Alexandre Oliva  <aoliva at redhat dot com>

	* sysdeps/ieee754/dbl-64/dbl2mpn.c (__mpn_extract_double):
	Cast shifted values that may be too narrow to mp_limb_t.
	* sysdeps/ieee754/dbl-64/mpn2dbl.c (__mpn_construct_double):
	Likewise.
	* sysdeps/ieee754/flt-32/mpn2flt.c (__mpn_construct_float):
	Likewise.
	* sysdeps/ieee754/ldbl-128/ldbl2mpn.c
	(__mpn_extract_long_double): Likewise.
	* sysdeps/ieee754/ldbl-128/mpn2ldbl.c
	(__mpn_construct_long_double): Likewise.
	* sysdeps/ieee754/ldbl-96/ldbl2mpn.c
	(__mpn_extract_long_double): Likewise.
	* sysdeps/ieee754/ldbl-96/mpn2ldbl.c
	(__mpn_construct_long_double): Likewise.

Index: sysdeps/ieee754/dbl-64/dbl2mpn.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/dbl-64/dbl2mpn.c,v
retrieving revision 1.2
diff -u -p -r1.2 dbl2mpn.c
--- sysdeps/ieee754/dbl-64/dbl2mpn.c 6 Jul 2001 04:55:54 -0000 1.2
+++ sysdeps/ieee754/dbl-64/dbl2mpn.c 14 Mar 2003 00:50:17 -0000
@@ -1,4 +1,5 @@
-/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
+/* Copyright (C) 1993, 1994, 1995, 1996, 1997, 2002, 2003
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -45,7 +46,7 @@ __mpn_extract_double (mp_ptr res_ptr, mp
 #elif BITS_PER_MP_LIMB == 64
   /* Hopefully the compiler will combine the two bitfield extracts
      and this composition into just the original quadword extract.  */
-  res_ptr[0] = ((unsigned long int) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
+  res_ptr[0] = ((mp_limb_t) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
   #define N 1
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
@@ -101,7 +102,8 @@ __mpn_extract_double (mp_ptr res_ptr, mp
     }
   else
     /* Add the implicit leading one bit for a normalized number.  */
-    res_ptr[N - 1] |= 1L << (DBL_MANT_DIG - 1 - ((N - 1) * BITS_PER_MP_LIMB));
+    res_ptr[N - 1] |= (mp_limb_t) 1 << (DBL_MANT_DIG - 1
+					- ((N - 1) * BITS_PER_MP_LIMB));
 
   return N;
 }
Index: sysdeps/ieee754/dbl-64/mpn2dbl.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/dbl-64/mpn2dbl.c,v
retrieving revision 1.2
diff -u -p -r1.2 mpn2dbl.c
--- sysdeps/ieee754/dbl-64/mpn2dbl.c 6 Jul 2001 04:55:55 -0000 1.2
+++ sysdeps/ieee754/dbl-64/mpn2dbl.c 14 Mar 2003 00:50:18 -0000
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1996, 1997, 2002, 2003 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -34,10 +34,12 @@ __mpn_construct_double (mp_srcptr frac_p
   u.ieee.exponent = expt + IEEE754_DOUBLE_BIAS;
 #if BITS_PER_MP_LIMB == 32
   u.ieee.mantissa1 = frac_ptr[0];
-  u.ieee.mantissa0 = frac_ptr[1] & ((1 << (DBL_MANT_DIG - 32)) - 1);
+  u.ieee.mantissa0 = frac_ptr[1] & (((mp_limb_t) 1
+				     << (DBL_MANT_DIG - 32)) - 1);
 #elif BITS_PER_MP_LIMB == 64
-  u.ieee.mantissa1 = frac_ptr[0] & ((1L << 32) - 1);
-  u.ieee.mantissa0 = (frac_ptr[0] >> 32) & ((1 << (DBL_MANT_DIG - 32)) - 1);
+  u.ieee.mantissa1 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
+  u.ieee.mantissa0 = (frac_ptr[0] >> 32) & (((mp_limb_t) 1
+					     << (DBL_MANT_DIG - 32)) - 1);
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
 #endif
Index: sysdeps/ieee754/flt-32/mpn2flt.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/flt-32/mpn2flt.c,v
retrieving revision 1.2
diff -u -p -r1.2 mpn2flt.c
--- sysdeps/ieee754/flt-32/mpn2flt.c 6 Jul 2001 04:55:55 -0000 1.2
+++ sysdeps/ieee754/flt-32/mpn2flt.c 14 Mar 2003 00:50:18 -0000
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995, 1997 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1997, 2002, 2003 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -33,7 +33,7 @@ __mpn_construct_float (mp_srcptr frac_pt
   u.ieee.negative = sign;
   u.ieee.exponent = expt + IEEE754_FLOAT_BIAS;
 #if BITS_PER_MP_LIMB > FLT_MANT_DIG
-  u.ieee.mantissa = frac_ptr[0] & ((1 << FLT_MANT_DIG) - 1);
+  u.ieee.mantissa = frac_ptr[0] & (((mp_limb_t) 1 << FLT_MANT_DIG) - 1);
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
 #endif
Index: sysdeps/ieee754/ldbl-128/ldbl2mpn.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/ldbl-128/ldbl2mpn.c,v
retrieving revision 1.3
diff -u -p -r1.3 ldbl2mpn.c
--- sysdeps/ieee754/ldbl-128/ldbl2mpn.c 11 Jul 2002 03:10:27 -0000 1.3
+++ sysdeps/ieee754/ldbl-128/ldbl2mpn.c 14 Mar 2003 00:50:19 -0000
@@ -1,4 +1,5 @@
-/* Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2002, 2003
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -49,8 +50,8 @@ __mpn_extract_long_double (mp_ptr res_pt
 #elif BITS_PER_MP_LIMB == 64
   /* Hopefully the compiler will combine the two bitfield extracts
      and this composition into just the original quadword extract.  */
-  res_ptr[0] = ((unsigned long int) u.ieee.mantissa2 << 32) | u.ieee.mantissa3;
-  res_ptr[1] = ((unsigned long int) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
+  res_ptr[0] = ((mp_limb_t) u.ieee.mantissa2 << 32) | u.ieee.mantissa3;
+  res_ptr[1] = ((mp_limb_t) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
   #define N 2
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
@@ -133,7 +134,8 @@ __mpn_extract_long_double (mp_ptr res_pt
     }
   else
     /* Add the implicit leading one bit for a normalized number.  */
-    res_ptr[N - 1] |= 1L << (LDBL_MANT_DIG - 1 - ((N - 1) * BITS_PER_MP_LIMB));
+    res_ptr[N - 1] |= (mp_limb_t) 1 << (LDBL_MANT_DIG - 1
+					- ((N - 1) * BITS_PER_MP_LIMB));
 
   return N;
 }
Index: sysdeps/ieee754/ldbl-128/mpn2ldbl.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/ldbl-128/mpn2ldbl.c,v
retrieving revision 1.2
diff -u -p -r1.2 mpn2ldbl.c
--- sysdeps/ieee754/ldbl-128/mpn2ldbl.c 6 Jul 2001 04:55:55 -0000 1.2
+++ sysdeps/ieee754/ldbl-128/mpn2ldbl.c 14 Mar 2003 00:50:19 -0000
@@ -1,4 +1,5 @@
-/* Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1996, 1997, 1998, 1999, 2002, 2003
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -37,12 +38,14 @@ __mpn_construct_long_double (mp_srcptr f
   u.ieee.mantissa3 = frac_ptr[0];
   u.ieee.mantissa2 = frac_ptr[1];
   u.ieee.mantissa1 = frac_ptr[2];
-  u.ieee.mantissa0 = frac_ptr[3] & ((1 << (LDBL_MANT_DIG - 96)) - 1);
+  u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1
+				     << (LDBL_MANT_DIG - 96)) - 1);
 #elif BITS_PER_MP_LIMB == 64
-  u.ieee.mantissa3 = frac_ptr[0] & ((1L << 32) - 1);
+  u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
   u.ieee.mantissa2 = frac_ptr[0] >> 32;
-  u.ieee.mantissa1 = frac_ptr[1] & ((1L << 32) - 1);
-  u.ieee.mantissa0 = (frac_ptr[1] >> 32) & ((1 << (LDBL_MANT_DIG - 96)) - 1);
+  u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1);
+  u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1
+					     << (LDBL_MANT_DIG - 96)) - 1);
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
 #endif
Index: sysdeps/ieee754/ldbl-96/ldbl2mpn.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/ldbl-96/ldbl2mpn.c,v
retrieving revision 1.2
diff -u -p -r1.2 ldbl2mpn.c
--- sysdeps/ieee754/ldbl-96/ldbl2mpn.c 6 Jul 2001 04:55:55 -0000 1.2
+++ sysdeps/ieee754/ldbl-96/ldbl2mpn.c 14 Mar 2003 00:50:19 -0000
@@ -1,4 +1,5 @@
-/* Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1996, 1997, 1998, 2002, 2003
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -47,7 +48,7 @@ __mpn_extract_long_double (mp_ptr res_pt
 #elif BITS_PER_MP_LIMB == 64
   /* Hopefully the compiler will combine the two bitfield extracts
      and this composition into just the original quadword extract.  */
-  res_ptr[0] = ((unsigned long int) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
+  res_ptr[0] = ((mp_limb_t) u.ieee.mantissa0 << 32) | u.ieee.mantissa1;
   #define N 1
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
Index: sysdeps/ieee754/ldbl-96/mpn2ldbl.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/ieee754/ldbl-96/mpn2ldbl.c,v
retrieving revision 1.2
diff -u -p -r1.2 mpn2ldbl.c
--- sysdeps/ieee754/ldbl-96/mpn2ldbl.c 6 Jul 2001 04:55:55 -0000 1.2
+++ sysdeps/ieee754/ldbl-96/mpn2ldbl.c 14 Mar 2003 00:50:19 -0000
@@ -1,4 +1,5 @@
-/* Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
+/* Copyright (C) 1995, 1996, 1997, 1998, 2002, 2003
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -37,7 +38,7 @@ __mpn_construct_long_double (mp_srcptr f
   u.ieee.mantissa1 = frac_ptr[0];
   u.ieee.mantissa0 = frac_ptr[1];
 #elif BITS_PER_MP_LIMB == 64
-  u.ieee.mantissa1 = frac_ptr[0] & ((1L << 32) - 1);
+  u.ieee.mantissa1 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
   u.ieee.mantissa0 = frac_ptr[0] >> 32;
 #else
   #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                 aoliva at {redhat dot com, gcc.gnu.org}
CS PhD student at IC-Unicamp        oliva at {lsd dot ic dot unicamp dot br, gnu.org}
Free Software Evangelist                Professional serial bug killer

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