Fix spurious "inexact" exceptions from x86 pow with NaN argument (bug 16167).

6 files changed, 36 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 574e07e..ce26384 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2013-11-16  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #16167]
+	* sysdeps/i386/fpu/e_pow.S (__ieee754_pow): Check for first
+	argument being NaN and avoid computations with second argument in
+	that case.
+	* sysdeps/i386/fpu/e_powf.S (__ieee754_powf): Likewise.
+	* sysdeps/i386/fpu/e_powl.S (__ieee754_powl): Likewise.
+	* sysdeps/x86_64/fpu/e_powl.S (__ieee754_powl): Likewise.
+
 2013-11-15  Arun Kumar Pyasi <arun@chitwanix.com>
 
 	* locale/iso-639.def: Add Chitwani Tharu (the).
diff --git a/NEWS b/NEWS
index 37c2390..e3effb6 100644
--- a/NEWS
+++ b/NEWS
@@ -18,7 +18,7 @@ Version 2.19
   15887, 15890, 15892, 15893, 15895, 15897, 15905, 15909, 15917, 15919,
   15921, 15923, 15939, 15948, 15963, 15966, 15985, 15988, 15997, 16032,
   16034, 16036, 16037, 16041, 16071, 16072, 16074, 16078, 16103, 16112,
-  16143, 16150, 16151, 16153, 16172.
+  16143, 16150, 16151, 16153, 16167, 16172.
 
 * CVE-2012-4412 The strcoll implementation caches indices and rules for
   large collation sequences to optimize multiple passes.  This cache
diff --git a/sysdeps/i386/fpu/e_pow.S b/sysdeps/i386/fpu/e_pow.S
index 109c395..835c39b 100644
--- a/sysdeps/i386/fpu/e_pow.S
+++ b/sysdeps/i386/fpu/e_pow.S
@@ -98,6 +98,9 @@ ENTRY(__ieee754_pow)
 	cmpb	$0x05, %ah
 	je	15f		// x is ħinf
 
+	cmpb	$0x01, %ah
+	je	32f		// x is NaN
+
 	fxch			// y : x
 
 	/* fistpll raises invalid exception for |y| >= 1L<<63.  */
@@ -166,6 +169,12 @@ ENTRY(__ieee754_pow)
 	ret
 
 	cfi_adjust_cfa_offset (8)
+32:	addl	$8, %esp
+	cfi_adjust_cfa_offset (-8)
+	fstp	%st(1)
+	ret
+
+	cfi_adjust_cfa_offset (8)
 	.align ALIGNARG(4)
 2:	// y is a large integer (absolute value at least 1L<<10), but
 	// may be odd unless at least 1L<<64.  So it may be necessary
diff --git a/sysdeps/i386/fpu/e_powf.S b/sysdeps/i386/fpu/e_powf.S
index 7fad90f..90d3d0c 100644
--- a/sysdeps/i386/fpu/e_powf.S
+++ b/sysdeps/i386/fpu/e_powf.S
@@ -95,6 +95,9 @@ ENTRY(__ieee754_powf)
 	cmpb	$0x05, %ah
 	je	15f		// x is ħinf
 
+	cmpb	$0x01, %ah
+	je	32f		// x is NaN
+
 	fxch			// y : x
 
 	/* fistpl raises invalid exception for |y| >= 1L<<31.  */
@@ -180,7 +183,7 @@ ENTRY(__ieee754_powf)
 	f2xm1			// 2^fract(y*log2(x))-1 : int(y*log2(x))
 	faddl	MO(one)		// 2^fract(y*log2(x)) : int(y*log2(x))
 	fscale			// 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
-	addl	$4, %esp
+32:	addl	$4, %esp
 	cfi_adjust_cfa_offset (-4)
 	fstp	%st(1)		// 2^fract(y*log2(x))*2^int(y*log2(x))
 	ret
diff --git a/sysdeps/i386/fpu/e_powl.S b/sysdeps/i386/fpu/e_powl.S
index 3c23117..91e22c8 100644
--- a/sysdeps/i386/fpu/e_powl.S
+++ b/sysdeps/i386/fpu/e_powl.S
@@ -104,6 +104,9 @@ ENTRY(__ieee754_powl)
 	cmpb	$0x05, %ah
 	je	15f		// x is ħinf
 
+	cmpb	$0x01, %ah
+	je	32f		// x is NaN
+
 	fxch			// y : x
 
 	/* fistpll raises invalid exception for |y| >= 1L<<63.  */
@@ -188,6 +191,12 @@ ENTRY(__ieee754_powl)
 	ret
 
 	cfi_adjust_cfa_offset (8)
+32:	addl	$8, %esp
+	cfi_adjust_cfa_offset (-8)
+	fstp	%st(1)
+	ret
+
+	cfi_adjust_cfa_offset (8)
 	.align ALIGNARG(4)
 2:	// y is a large integer (absolute value at least 8), but
 	// may be odd unless at least 1L<<64.  So it may be necessary
diff --git a/sysdeps/x86_64/fpu/e_powl.S b/sysdeps/x86_64/fpu/e_powl.S
index e101726..590223b 100644
--- a/sysdeps/x86_64/fpu/e_powl.S
+++ b/sysdeps/x86_64/fpu/e_powl.S
@@ -96,6 +96,9 @@ ENTRY(__ieee754_powl)
 	cmpb	$0x05, %ah
 	je	15f		// x is ħinf
 
+	cmpb	$0x01, %ah
+	je	31f		// x is NaN
+
 	fxch			// y : x
 
 	/* fistpll raises invalid exception for |y| >= 1L<<63.  */