From: Andrew Waterman <andrew@sifive.com>
Date: Thu, 22 Feb 2018 19:31:54 +0000 (-0500)
Subject: RISC-V: fmax/fmin: Handle signalling NaNs correctly.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aab08776cc8f6dbafaa6efcb7e1bb374a21ab823;p=thirdparty%2Fglibc.git

RISC-V: fmax/fmin: Handle signalling NaNs correctly.

RISC-V's fmax(sNAN,4) returns 4 but glibc expects it to return qNAN.

	* sysdeps/riscv/rvd/s_fmax.c (__fmax): Handle sNaNs correctly.
	* sysdeps/riscv/rvd/s_fmin.c (__fmin): Likewise.
	* sysdeps/riscv/rvf/s_fmaxf.c (__fmaxf): Likewise.
	* sysdeps/riscv/rvf/s_fminf.c (__fminf): Likewise.

(cherry picked from commit fdcc625376505eacb1125a6aeba57501407a30ec)
---

diff --git a/ChangeLog b/ChangeLog
index 8b859f637d6..394f6703638 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2018-02-22  Andrew Waterman <andrew@sifive.com>
+
+	* sysdeps/riscv/rvd/s_fmax.c (__fmax): Handle sNaNs correctly.
+	* sysdeps/riscv/rvd/s_fmin.c (__fmin): Likewise.
+	* sysdeps/riscv/rvf/s_fmaxf.c (__fmaxf): Likewise.
+	* sysdeps/riscv/rvf/s_fminf.c (__fminf): Likewise.
+
 2018-02-22  DJ Delorie  <dj@delorie.com>
 
 	* sysdeps/riscv/tls-macros.h: Do not initialize $gp.
diff --git a/sysdeps/riscv/rvd/s_fmax.c b/sysdeps/riscv/rvd/s_fmax.c
index ef8f1344ce5..22e91bfc4b8 100644
--- a/sysdeps/riscv/rvd/s_fmax.c
+++ b/sysdeps/riscv/rvd/s_fmax.c
@@ -17,12 +17,19 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <math.h>
+#include <math_private.h>
 #include <libm-alias-double.h>
 
 double
 __fmax (double x, double y)
 {
-  asm ("fmax.d %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
-  return x;
+  double res;
+
+  if (__glibc_unlikely ((_FCLASS (x) | _FCLASS (y)) & _FCLASS_SNAN))
+    return x + y;
+  else
+    asm ("fmax.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+
+  return res;
 }
 libm_alias_double (__fmax, fmax)
diff --git a/sysdeps/riscv/rvd/s_fmin.c b/sysdeps/riscv/rvd/s_fmin.c
index c6ff24cefb8..7b35230cacd 100644
--- a/sysdeps/riscv/rvd/s_fmin.c
+++ b/sysdeps/riscv/rvd/s_fmin.c
@@ -17,12 +17,19 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <math.h>
+#include <math_private.h>
 #include <libm-alias-double.h>
 
 double
 __fmin (double x, double y)
 {
-  asm ("fmin.d %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
-  return x;
+  double res;
+
+  if (__glibc_unlikely ((_FCLASS (x) | _FCLASS (y)) & _FCLASS_SNAN))
+    return x + y;
+  else
+    asm ("fmin.d %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+
+  return res;
 }
 libm_alias_double (__fmin, fmin)
diff --git a/sysdeps/riscv/rvf/s_fmaxf.c b/sysdeps/riscv/rvf/s_fmaxf.c
index 3293f2f41ca..63f7e3d6648 100644
--- a/sysdeps/riscv/rvf/s_fmaxf.c
+++ b/sysdeps/riscv/rvf/s_fmaxf.c
@@ -17,12 +17,19 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <math.h>
+#include <math_private.h>
 #include <libm-alias-float.h>
 
 float
 __fmaxf (float x, float y)
 {
-  asm ("fmax.s %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
-  return x;
+  float res;
+
+  if (__glibc_unlikely ((_FCLASS (x) | _FCLASS (y)) & _FCLASS_SNAN))
+    return x + y;
+  else
+    asm ("fmax.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+
+  return res;
 }
 libm_alias_float (__fmax, fmax)
diff --git a/sysdeps/riscv/rvf/s_fminf.c b/sysdeps/riscv/rvf/s_fminf.c
index e4411f04b25..82cca4e37d8 100644
--- a/sysdeps/riscv/rvf/s_fminf.c
+++ b/sysdeps/riscv/rvf/s_fminf.c
@@ -17,12 +17,19 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <math.h>
+#include <math_private.h>
 #include <libm-alias-float.h>
 
 float
 __fminf (float x, float y)
 {
-  asm ("fmin.s %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
-  return x;
+  float res;
+
+  if (__glibc_unlikely ((_FCLASS (x) | _FCLASS (y)) & _FCLASS_SNAN))
+    return x + y;
+  else
+    asm ("fmin.s %0, %1, %2" : "=f" (res) : "f" (x), "f" (y));
+
+  return res;
 }
 libm_alias_float (__fmin, fmin)