From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>
Date: Sun, 6 Apr 2014 19:50:11 +0000 (-0500)
Subject: PowerPC: Fix nearbyint/nearbyintf result for FE_DOWNWARD
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=154d4d95f48061d5ab890c85b6015221c1accc6e;p=thirdparty%2Fglibc.git

PowerPC: Fix nearbyint/nearbyintf result for FE_DOWNWARD

This patch fixes the powerpc32 optimized nearbyint/nearbyintf bogus
results for FE_DOWNWARD rounding mode.  This is due wrong instructions
sequence used in the rounding calculation (two subtractions instead of
adition and a subtraction).

Fixes BZ#16815.

Backport of 8bd70862e11023e7f827f240a5a214f847ae982d.
---

diff --git a/ChangeLog b/ChangeLog
index 5bf3e2667ab..c28708f3fd2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2014-04-06  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
+
+	[BZ #16815]
+	* sysdeps/powerpc/powerpc32/fpu/s_nearbyint.S (__nearbyint): Fix
+	result for FE_DOWNWARD rounding mode.
+	* sysdeps/powerpc/powerpc32/fpu/s_nearbyintf.S (__nearbyintf):
+	Likewise.
+	* sysdeps/powerpc/fpu/libm-test-ulps: Update.
+
 2014-04-02  Alan Modra  <amodra@gmail.com>
 
 	[BZ #16739]
diff --git a/NEWS b/NEWS
index 71f6fb6618d..a49629437ab 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,7 @@ Version 2.19.1
 
 * The following bugs are resolved with this release:
 
-  16545, 16683, 16689, 16701, 16706, 16707, 16739.
+  16545, 16683, 16689, 16701, 16706, 16707, 16739, 16815.
 
 Version 2.19
 
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_nearbyint.S b/sysdeps/powerpc/powerpc32/fpu/s_nearbyint.S
index 2734738d4d0..05ab40ecb51 100644
--- a/sysdeps/powerpc/powerpc32/fpu/s_nearbyint.S
+++ b/sysdeps/powerpc/powerpc32/fpu/s_nearbyint.S
@@ -53,17 +53,17 @@ ENTRY (__nearbyint)
 	fcmpu	cr7,fp1,fp12	/* if (x > 0.0 */
 	ble	cr7,L(lessthanzero)
 	mtfsb0	4*cr7+lt	/* Disable FE_INEXACT exception */
-	fadd	fp0,fp1,fp13	/* x += TWO52 */
-	fsub	fp1,fp0,fp13	/* x -= TWO52 */
+	fadd	fp1,fp1,fp13	/* x += TWO52 */
+	fsub	fp1,fp1,fp13	/* x -= TWO52 */
 	fabs	fp1,fp1		/* if (x == 0.0 */
 	mtfsb0	4*cr1+eq	/* Clear any FE_INEXACT exception */
 	blr
 L(lessthanzero):
 	bgelr	cr7
 	mtfsb0	4*cr7+lt	/* Disable FE_INEXACT exception */
-	fsub	fp0,fp13,fp1	/* x -= TWO52 */
-	fsub	fp0,fp0,fp13	/* x += TWO52 */
-	fneg	fp1,fp0		/* if (x == 0.0) */
+	fsub	fp1,fp1,fp13	/* x -= TWO52 */
+	fadd	fp1,fp1,fp13	/* x += TWO52 */
+	fnabs	fp1,fp1		/* if (x == 0.0) */
 	mtfsb0	4*cr1+eq	/* Clear any FE_INEXACT exception */
 	blr
 END (__nearbyint)
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_nearbyintf.S b/sysdeps/powerpc/powerpc32/fpu/s_nearbyintf.S
index 11bdc773705..7449a5f9b79 100644
--- a/sysdeps/powerpc/powerpc32/fpu/s_nearbyintf.S
+++ b/sysdeps/powerpc/powerpc32/fpu/s_nearbyintf.S
@@ -52,16 +52,17 @@ ENTRY (__nearbyintf)
 	fcmpu	cr7,fp1,fp12		/* if (x > 0.0 */
 	ble	cr7,L(lessthanzero)
 	mtfsb0	4*cr7+lt		/* Disable FE_INEXACT exception */
-	fadds	fp0,fp1,fp13		/* x += TWO23 */
-	fsubs	fp1,fp0,fp13		/* x -= TWO23 */
+	fadds	fp1,fp1,fp13		/* x += TWO23 */
+	fsubs	fp1,fp1,fp13		/* x -= TWO23 */
+	fabs	fp1,fp1			/* if (x == 0.0) */
 	mtfsb0	4*cr1+eq		/* Clear any FE_INEXACT exception */
 	blr
 L(lessthanzero):
 	bgelr	cr7
 	mtfsb0	4*cr7+lt		/* Disable FE_INEXACT exception */
-	fsubs	fp0,fp13,fp1		/* x -= TWO23 */
-	fsubs	fp0,fp0,fp13		/* x += TWO23 */
-	fneg	fp1,fp0			/* if (x == 0.0) */
+	fsubs	fp1,fp1,fp13		/* x -= TWO23 */
+	fadds	fp1,fp1,fp13		/* x += TWO23 */
+	fnabs	fp1,fp1			/* if (x == 0.0) */
 	mtfsb0	4*cr1+eq		/* Clear any FE_INEXACT exception */
 	blr
 END (__nearbyintf)