[newlib-cygwin] newlib/libm/common: Fix modf/modff returning snan

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=61cd34c1bfab626c084fd4289657b8f1ac43a138

commit 61cd34c1bfab626c084fd4289657b8f1ac43a138
Author: Keith Packard via Newlib <newlib@sourceware.org>
Date:   Wed Mar 25 17:18:19 2020 -0700

    newlib/libm/common: Fix modf/modff returning snan
    
    Recent GCC appears to elide multiplication by 1, which causes snan
    parameters to be returned unchanged through *iptr. Use the existing
    conversion of snan to qnan to also set the correct result in *iptr
    instead.
    
    Signed-off-by: Keith Packard <keithp@keithp.com>

Diff:
---
 newlib/libm/common/s_modf.c  | 10 ++--------
 newlib/libm/common/sf_modf.c | 10 ++--------
 2 files changed, 4 insertions(+), 16 deletions(-)

diff --git a/newlib/libm/common/s_modf.c b/newlib/libm/common/s_modf.c
index c948b8525..c826580b4 100644
--- a/newlib/libm/common/s_modf.c
+++ b/newlib/libm/common/s_modf.c
@@ -63,12 +63,6 @@ QUICKREF
 
 #ifndef _DOUBLE_IS_32BITS
 
-#ifdef __STDC__
-static const double one = 1.0;
-#else
-static double one = 1.0;
-#endif
-
 #ifdef __STDC__
 	double modf(double x, double *iptr)
 #else
@@ -99,8 +93,8 @@ static double one = 1.0;
 	    }
 	} else if (j0>51) {		/* no fraction part */
 	    __uint32_t high;
-	    *iptr = x*one;
-	    if (__fpclassifyd(x) == FP_NAN) return x+x; /* x is NaN, return NaN */
+	    *iptr = x;
+	    if (__fpclassifyd(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
 	    GET_HIGH_WORD(high,x);
 	    INSERT_WORDS(x,high&0x80000000,0);	/* return +-0 */
 	    return x;
diff --git a/newlib/libm/common/sf_modf.c b/newlib/libm/common/sf_modf.c
index ae970762b..e241e4612 100644
--- a/newlib/libm/common/sf_modf.c
+++ b/newlib/libm/common/sf_modf.c
@@ -15,12 +15,6 @@
 
 #include "fdlibm.h"
 
-#ifdef __STDC__
-static const float one = 1.0;
-#else
-static float one = 1.0;
-#endif
-
 #ifdef __STDC__
 	float modff(float x, float *iptr)
 #else
@@ -51,8 +45,8 @@ static float one = 1.0;
 	    }
 	} else {			/* no fraction part */
 	    __uint32_t ix;
-	    *iptr = x*one;
-	    if (__fpclassifyf(x) == FP_NAN) return x+x; /* x is NaN, return NaN */
+	    *iptr = x;
+	    if (__fpclassifyf(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
 	    GET_FLOAT_WORD(ix,x);
 	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
 	    return x;