From 05f3ed0a799d08c2b3ecc256fc0dc08d8b9a3784 Mon Sep 17 00:00:00 2001
From: Joseph Myers <joseph@codesourcery.com>
Date: Wed, 19 Oct 2016 22:58:34 +0000
Subject: [PATCH] Stop powerpc copysignl raising "invalid" for sNaN argument
 (bug 20718).

The powerpc (hard-float) implementations of copysignl, both 32-bit and
64-bit, raise spurious "invalid" exceptions when the first argument is
a signaling NaN.  copysign functions should never raise exceptions
even for signaling NaNs.

The problem is the use of an fcmpu instruction to test the sign of the
high part of the long double argument.  This patch fixes the functions
to use fsel instead (as used for fabsl following my fixes for a
similar bug there), or to examine the integer representation for older
32-bit processors without fsel.

Tested for powerpc64 and powerpc32 (configurations with and without
fsel used).

	[BZ #20718]
	* sysdeps/powerpc/powerpc32/fpu/s_copysignl.S (__copysignl): Do
	not use floating-point comparisons to test sign.
	* sysdeps/powerpc/powerpc64/fpu/s_copysignl.S (__copysignl):
	Likewise.
---
 ChangeLog                                   |  6 ++++++
 sysdeps/powerpc/powerpc32/fpu/s_copysignl.S | 23 ++++++++++++++++++++---
 sysdeps/powerpc/powerpc64/fpu/s_copysignl.S | 10 ++++------
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9b226786af..49436bcf4b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2016-10-19  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #20718]
+	* sysdeps/powerpc/powerpc32/fpu/s_copysignl.S (__copysignl): Do
+	not use floating-point comparisons to test sign.
+	* sysdeps/powerpc/powerpc64/fpu/s_copysignl.S (__copysignl):
+	Likewise.
+
 	* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
 	(getpayload): New declaration.
 	* math/Versions (getpayload): New libm symbol at version
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_copysignl.S b/sysdeps/powerpc/powerpc32/fpu/s_copysignl.S
index aed783ad59..1eec8474ed 100644
--- a/sysdeps/powerpc/powerpc32/fpu/s_copysignl.S
+++ b/sysdeps/powerpc/powerpc32/fpu/s_copysignl.S
@@ -24,22 +24,39 @@ ENTRY(__copysignl)
 /* long double [f1,f2] copysign (long double [f1,f2] x, long double [f3,f4] y);
    copysign(x,y) returns a value with the magnitude of x and
    with the sign bit of y.  */
+#ifdef _ARCH_PPCGR
+	/* fsel available.  */
 	stwu	r1,-16(r1)
 	cfi_adjust_cfa_offset (16)
 	stfd	fp3,8(r1)
 	fmr	fp0,fp1
 	fabs	fp1,fp1
-	fcmpu	cr7,fp0,fp1
 	lwz	r3,8+HIWORD(r1)
 	cmpwi	cr6,r3,0
 	addi	r1,r1,16
 	cfi_adjust_cfa_offset (-16)
-	beq	cr7,L(0)
+	fneg	fp3,fp2
+	fsel	fp2,fp0,fp2,fp3
+	bgelr	cr6
+	fneg	fp1,fp1
 	fneg	fp2,fp2
-L(0):	bgelr	cr6
+	blr
+#else
+	stwu	r1,-32(r1)
+	cfi_adjust_cfa_offset (32)
+	stfd	fp3,8(r1)
+	stfd	fp1,16(r1)
+	lwz	r3,8+HIWORD(r1)
+	lwz	r4,16+HIWORD(r1)
+	xor	r3,r3,r4
+	cmpwi	cr6,r3,0
+	addi	r1,r1,32
+	cfi_adjust_cfa_offset (-32)
+	bgelr	cr6
 	fneg	fp1,fp1
 	fneg	fp2,fp2
 	blr
+#endif
 END (__copysignl)
 
 #if IS_IN (libm)
diff --git a/sysdeps/powerpc/powerpc64/fpu/s_copysignl.S b/sysdeps/powerpc/powerpc64/fpu/s_copysignl.S
index 1e1b9d43e6..548076d25b 100644
--- a/sysdeps/powerpc/powerpc64/fpu/s_copysignl.S
+++ b/sysdeps/powerpc/powerpc64/fpu/s_copysignl.S
@@ -30,16 +30,14 @@ ENTRY(__copysignl)
 	blt     L(0)
 	fmr	fp0,fp1
 	fabs	fp1,fp1
-	fcmpu	cr1,fp0,fp1
-	beqlr	cr1
-	fneg	fp2,fp2
+	fneg	fp3,fp2
+	fsel	fp2,fp0,fp2,fp3
 	blr
 L(0):
 	fmr	fp0,fp1
 	fnabs   fp1,fp1
-	fcmpu	cr1,fp0,fp1
-	beqlr	cr1
-	fneg	fp2,fp2
+	fneg	fp3,fp2
+	fsel	fp2,fp0,fp3,fp2
 	blr
 END (__copysignl)
 
-- 
2.11.4.GIT