fp-bit.c (unpack_d, pack_d): Properly preserve and restore a NaN's payload.

libgcc/
	* fp-bit.c (unpack_d, pack_d): Properly preserve and restore a
	NaN's payload.

From-SVN: r198622

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index e4e0d5700509976d30c4960a9469dbd75fe877ec..c874a84b6b06abd082cf0fb5aa372ad05a38441e 100644 (file)
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,5 +1,8 @@
 2013-05-06  Thomas Schwinge  <thomas@codesourcery.com>
 
+       * fp-bit.c (unpack_d, pack_d): Properly preserve and restore a
+       NaN's payload.
+
        * fp-bit.h [FLOAT] (QUIET_NAN): Correct value.
 
 2013-04-25  Alan Modra  <amodra@gmail.com>

diff --git a/libgcc/fp-bit.c b/libgcc/fp-bit.c
index 60f23387e8127681dc4933f62501c6725e9c8219..9b0c194604f81d82492da1e615c1b8b99d25af6f 100644 (file)
--- a/libgcc/fp-bit.c
+++ b/libgcc/fp-bit.c
@@ -213,11 +213,18 @@ pack_d (const fp_number_type *src)
   else if (isnan (src))
     {
       exp = EXPMAX;
+      /* Restore the NaN's payload.  */
+      fraction >>= NGARDS;
+      fraction &= QUIET_NAN - 1;
       if (src->class == CLASS_QNAN || 1)
        {
 #ifdef QUIET_NAN_NEGATED
-         fraction |= QUIET_NAN - 1;
+         /* The quiet/signaling bit remains unset.  */
+         /* Make sure the fraction has a non-zero value.  */
+         if (fraction == 0)
+           fraction |= QUIET_NAN - 1;
 #else
+         /* Set the quiet/signaling bit.  */
          fraction |= QUIET_NAN;
 #endif
        }
@@ -573,8 +580,10 @@ unpack_d (FLO_union_type * src, fp_number_type * dst)
            {
              dst->class = CLASS_SNAN;
            }
-         /* Keep the fraction part as the nan number */
-         dst->fraction.ll = fraction;
+         /* Now that we know which kind of NaN we got, discard the
+            quiet/signaling bit, but do preserve the NaN payload.  */
+         fraction &= ~QUIET_NAN;
+         dst->fraction.ll = fraction << NGARDS;
        }
     }
   else

diff --git a/libgcc/fp-bit.h b/libgcc/fp-bit.h
index 2ac504a56e5aa197fe060a31cd158291b392cb52..b6fe9f7a2880e8a721b32d944e3d1ea4b73625ad 100644 (file)
--- a/libgcc/fp-bit.h
+++ b/libgcc/fp-bit.h
@@ -297,7 +297,7 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
 /* numeric parameters */
 /* F_D_BITOFF is the number of bits offset between the MSB of the mantissa
    of a float and of a double. Assumes there are only two float types.
-   (double::FRAC_BITS+double::NGARDS-(float::FRAC_BITS-float::NGARDS))
+   (double::FRAC_BITS+double::NGARDS-(float::FRAC_BITS+float::NGARDS))
  */
 #define F_D_BITOFF (52+8-(23+7))