From 4ad9ba42fc3dd116bad8b9cb89d434256d3431fb Mon Sep 17 00:00:00 2001
From: Fabian Schriever <fabian.schriever@gtd-gmbh.de>
Date: Wed, 18 Mar 2020 14:18:20 +0100
Subject: [PATCH] Fix modf/f for NaN input

For NaN input the modf/f procedures should return NaN instead of zero
with the sign of the input.
---
 newlib/libm/common/s_modf.c  | 1 +
 newlib/libm/common/sf_modf.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/newlib/libm/common/s_modf.c b/newlib/libm/common/s_modf.c
index 8551a99e4..c948b8525 100644
--- a/newlib/libm/common/s_modf.c
+++ b/newlib/libm/common/s_modf.c
@@ -100,6 +100,7 @@ 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 */
 	    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 6c64e3fa0..ae970762b 100644
--- a/newlib/libm/common/sf_modf.c
+++ b/newlib/libm/common/sf_modf.c
@@ -52,6 +52,7 @@ 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 */
 	    GET_FLOAT_WORD(ix,x);
 	    SET_FLOAT_WORD(x,ix&0x80000000);	/* return +-0 */
 	    return x;