Fix frexp (NaN) (bug 20250).

Various implementations of frexp functions return sNaN for sNaN
input.  This patch fixes them to add such arguments to themselves so
that qNaN is returned.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #20250]
	* sysdeps/i386/fpu/s_frexpl.S (__frexpl): Add non-finite input to
	itself.
	* sysdeps/ieee754/dbl-64/s_frexp.c (__frexp): Add non-finite or
	zero input to itself.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c (__frexp):
	Likewise.
	* sysdeps/ieee754/flt-32/s_frexpf.c (__frexpf): Likewise.
	* sysdeps/ieee754/ldbl-128/s_frexpl.c (__frexpl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_frexpl.c (__frexpl): Likewise.
	* sysdeps/ieee754/ldbl-96/s_frexpl.c (__frexpl): Likewise.
	* math/libm-test.inc (frexp_test_data): Add sNaN tests.

7 files changed, 16 insertions, 6 deletions

diff --git a/sysdeps/i386/fpu/s_frexpl.S b/sysdeps/i386/fpu/s_frexpl.S
index f687ab3c2e..b33a8a8573 100644
--- a/sysdeps/i386/fpu/s_frexpl.S
+++ b/sysdeps/i386/fpu/s_frexpl.S
@@ -50,7 +50,7 @@ ENTRY (__frexpl)
 	jz	1f
 	xorl	%ecx, %ecx
 	cmpl	$0x7fff, %eax
-	je	1f
+	je	3f
 
 	cmpl	$0, %eax
 	jne	2f
@@ -81,5 +81,12 @@ ENTRY (__frexpl)
 	movl	%ecx, (%eax)
 
 	ret
+
+	/* Infinity or NaN; ensure signaling NaNs are quieted.  */
+3:	movl	EXPP(%esp), %eax
+	fldt	VAL0(%esp)
+	fadd	%st
+	movl	%ecx, (%eax)
+	ret
 END (__frexpl)
 weak_alias (__frexpl, frexpl)
diff --git a/sysdeps/ieee754/dbl-64/s_frexp.c b/sysdeps/ieee754/dbl-64/s_frexp.c
index 1b8d8500ba..874214ec7c 100644
--- a/sysdeps/ieee754/dbl-64/s_frexp.c
+++ b/sysdeps/ieee754/dbl-64/s_frexp.c
@@ -38,7 +38,7 @@ __frexp (double x, int *eptr)
   ix = 0x7fffffff & hx;
   *eptr = 0;
   if (ix >= 0x7ff00000 || ((ix | lx) == 0))
-    return x;                                           /* 0,inf,nan */
+    return x + x;                                           /* 0,inf,nan */
   if (ix < 0x00100000)                  /* subnormal */
     {
       x *= two54;
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c
index 42068f8187..4b075b7200 100644
--- a/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c
@@ -55,6 +55,9 @@ __frexp (double x, int *eptr)
       ix = (ix & INT64_C (0x800fffffffffffff)) | INT64_C (0x3fe0000000000000);
       INSERT_WORDS64 (x, ix);
     }
+  else
+    /* Quiet signaling NaNs.  */
+    x += x;
 
   *eptr = e;
   return x;
diff --git a/sysdeps/ieee754/flt-32/s_frexpf.c b/sysdeps/ieee754/flt-32/s_frexpf.c
index 67a28d3603..005367cf58 100644
--- a/sysdeps/ieee754/flt-32/s_frexpf.c
+++ b/sysdeps/ieee754/flt-32/s_frexpf.c
@@ -29,7 +29,7 @@ float __frexpf(float x, int *eptr)
 	GET_FLOAT_WORD(hx,x);
 	ix = 0x7fffffff&hx;
 	*eptr = 0;
-	if(ix>=0x7f800000||(ix==0)) return x;	/* 0,inf,nan */
+	if(ix>=0x7f800000||(ix==0)) return x + x;	/* 0,inf,nan */
 	if (ix<0x00800000) {		/* subnormal */
 	    x *= two25;
 	    GET_FLOAT_WORD(hx,x);
diff --git a/sysdeps/ieee754/ldbl-128/s_frexpl.c b/sysdeps/ieee754/ldbl-128/s_frexpl.c
index d61dddaaaa..70b2d3ae19 100644
--- a/sysdeps/ieee754/ldbl-128/s_frexpl.c
+++ b/sysdeps/ieee754/ldbl-128/s_frexpl.c
@@ -39,7 +39,7 @@ long double __frexpl(long double x, int *eptr)
 	GET_LDOUBLE_WORDS64(hx,lx,x);
 	ix = 0x7fffffffffffffffULL&hx;
 	*eptr = 0;
-	if(ix>=0x7fff000000000000ULL||((ix|lx)==0)) return x;	/* 0,inf,nan */
+	if(ix>=0x7fff000000000000ULL||((ix|lx)==0)) return x + x;/* 0,inf,nan */
 	if (ix<0x0001000000000000ULL) {		/* subnormal */
 	    x *= two114;
 	    GET_LDOUBLE_MSW64(hx,x);
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_frexpl.c b/sysdeps/ieee754/ldbl-128ibm/s_frexpl.c
index 52d2d3ea90..210c5d2ed4 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_frexpl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_frexpl.c
@@ -47,7 +47,7 @@ long double __frexpl(long double x, int *eptr)
     {
       /* 0,inf,nan.  */
       *eptr = expon;
-      return x;
+      return x + x;
     }
   expon = ix >> 52;
   if (expon == 0)
diff --git a/sysdeps/ieee754/ldbl-96/s_frexpl.c b/sysdeps/ieee754/ldbl-96/s_frexpl.c
index ab217a659b..799880f373 100644
--- a/sysdeps/ieee754/ldbl-96/s_frexpl.c
+++ b/sysdeps/ieee754/ldbl-96/s_frexpl.c
@@ -46,7 +46,7 @@ long double __frexpl(long double x, int *eptr)
 	GET_LDOUBLE_WORDS(se,hx,lx,x);
 	ix = 0x7fff&se;
 	*eptr = 0;
-	if(ix==0x7fff||((ix|hx|lx)==0)) return x;	/* 0,inf,nan */
+	if(ix==0x7fff||((ix|hx|lx)==0)) return x + x;	/* 0,inf,nan */
 	if (ix==0x0000) {		/* subnormal */
 	    x *= two65;
 	    GET_LDOUBLE_EXP(se,x);