PowerPC: fix hypot/hypof FP exceptions

This patch fixes hypot/hypotf spurious floating-point exceptions
generate by internal operations.

5 files changed, 25 insertions, 17 deletions

diff --git a/ChangeLog b/ChangeLog
index 1c43908d62..4bf30b6c57 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2013-05-06  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
+
+	[BZ #15418]
+	[BZ #15419]
+	* sysdeps/powerpc/fpu/e_hypot.c: Fix spurious FP exception generated by
+	internal tests.
+	* sysdeps/powerpc/fpu/e_hypotf.c: Likewise.
+
 2013-05-06  Roland McGrath  <roland@hack.frob.com>
 
 	* elf/dl-writev.h: New file.
diff --git a/NEWS b/NEWS
index ce654c1e5c..95a4e4f4c3 100644
--- a/NEWS
+++ b/NEWS
@@ -16,7 +16,7 @@ Version 2.18
   15084, 15085, 15086, 15160, 15214, 15221, 15232, 15234, 15283, 15285,
   15287, 15304, 15305, 15307, 15309, 15327, 15330, 15335, 15336, 15337,
   15342, 15346, 15361, 15366, 15380, 15394, 15405, 15406, 15409, 15416,
-  15423.
+  15418, 15419, 15423.
 
 * CVE-2013-0242 Buffer overrun in regexp matcher has been fixed (Bugzilla
   #15078).
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 4e1eb72919..7afa46dba8 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -9159,6 +9159,7 @@ hypot_test (void)
   TEST_ff_f (hypot, 0.75L, 1.25L, 1.45773797371132511771853821938639577L);
 
   TEST_ff_f (hypot, 1.0L, 0x1p-61L, 1.0L);
+  TEST_ff_f (hypot, 0x1p+0L, 0x1.fp-129L, 0x1p+0L);
 #if defined TEST_LDOUBLE && LDBL_MANT_DIG >= 106
   TEST_ff_f (hypot, 0x1.23456789abcdef0123456789ab8p-500L, 0x1.23456789abcdef0123456789ab8p-500L, 4.9155782399407039128612180934736799735113e-151L);
 #endif
@@ -9170,6 +9171,7 @@ hypot_test (void)
 
 #if !defined TEST_FLOAT && !(defined TEST_DOUBLE && defined TEST_INLINE)
   TEST_ff_f (hypot, 0x3p1021L, 0x4p1021L, 0x5p1021L);
+  TEST_ff_f (hypot, 0x1p+0L, 0x0.3ep-1022L, 0x1p+0L);
 #endif
 
 #if defined TEST_LDOUBLE && LDBL_MAX_EXP >= 16384 && !defined TEST_INLINE
diff --git a/sysdeps/powerpc/fpu/e_hypot.c b/sysdeps/powerpc/fpu/e_hypot.c
index f23633946f..d8568d6e3f 100644
--- a/sysdeps/powerpc/fpu/e_hypot.c
+++ b/sysdeps/powerpc/fpu/e_hypot.c
@@ -26,6 +26,7 @@ static const double two600  = 4.149515568880993e+180;
 static const double two1022 = 4.49423283715579e+307;
 static const double twoM500 = 3.054936363499605e-151;
 static const double twoM600 = 2.4099198651028841e-181;
+static const double two60factor = 1.5592502418239997e+290;
 static const double pdnum   = 2.225073858507201e-308;
 
 /* __ieee754_hypot(x,y)
@@ -87,9 +88,20 @@ __ieee754_hypot (double x, double y)
       x = y;
       y = t;
     }
-  if (y == 0.0 || (x / y) > two60)
+  if (y == 0.0)
+    return x;
+  /* if y is higher enough, y * 2^60 might overflow. The tests if
+     y >= 1.7976931348623157e+308/2^60 (two60factor) and uses the
+     appropriate check to avoid the overflow exception generation.  */
+  if (y > two60factor)
     {
-      return x + y;
+      if ((x / y) > two60)
+	return x + y;
+    }
+  else
+    {
+      if (x > (y * two60))
+	return x + y;
     }
   if (x > two500)
     {
diff --git a/sysdeps/powerpc/fpu/e_hypotf.c b/sysdeps/powerpc/fpu/e_hypotf.c
index e97f0c35e3..93055afce5 100644
--- a/sysdeps/powerpc/fpu/e_hypotf.c
+++ b/sysdeps/powerpc/fpu/e_hypotf.c
@@ -69,22 +69,8 @@ static const float two30  = 1.0737418e09;
 float
 __ieee754_hypotf (float x, float y)
 {
-  x = fabsf (x);
-  y = fabsf (y);
-
   TEST_INF_NAN (x, y);
 
-  if (y > x)
-    {
-      float t = y;
-      y = x;
-      x = t;
-    }
-  if (y == 0.0 || (x / y) > two30)
-    {
-      return x + y;
-    }
-
   return __ieee754_sqrt ((double) x * x + (double) y * y);
 }
 strong_alias (__ieee754_hypotf, __hypotf_finite)