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Avoid uninitialized warnings in Bessel functions [committed]


math/Makefile currently has:

  # The fdlibm code generates a lot of these warnings but is otherwise clean.
  override CFLAGS += -Wno-uninitialized

This is of course undesirable; warnings should be disabled as narrowly
as possible.  To remove this override, we need to fix files that
generate such warnings, or put warning-disabling pragmas in them.
This patch does so for Bessel function implementations, one of the
cases that have the warnings if the override is removed.  The warnings
arise because functions set pointer variables p and q only for certain
values of the function argument, then use them unconditionally.  As
the static functions in question only get called for arguments that
satisfy the last condition in the if/else chain, the natural fix is to
change the last "else if" to just "else", which this patch does.  (The
ldbl-128 / ldbl-128ibm implementation of these functions is
substantially different and looks like it already does use "else" in
the last case in the nearest corresponding code.)

Tested for x86_64 and x86.  Committed.

2015-02-26  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/ieee754/dbl-64/e_j0.c (pzero): Change last case for
	setting p and q from "else if" to "else".
	(qzero): Likewise.
	* sysdeps/ieee754/dbl-64/e_j1.c (pone): Likewise.
	(qone): Likewise.
	* sysdeps/ieee754/flt-32/e_j0f.c (pzerof): Likewise.
	(qzerof): Likewise.
	* sysdeps/ieee754/flt-32/e_j1f.c (ponef): Likewise.
	(qonef): Likewise.
	* sysdeps/ieee754/ldbl-96/e_j0l.c (pzero): Likewise.
	(qzero): Likewise.
	* sysdeps/ieee754/ldbl-96/e_j1l.c (pone): Likewise.
	(qone): Likewise.

diff --git a/sysdeps/ieee754/dbl-64/e_j0.c b/sysdeps/ieee754/dbl-64/e_j0.c
index d165e80..9f25aa8 100644
--- a/sysdeps/ieee754/dbl-64/e_j0.c
+++ b/sysdeps/ieee754/dbl-64/e_j0.c
@@ -305,6 +305,7 @@ pzero (double x)
   int32_t ix;
   GET_HIGH_WORD (ix, x);
   ix &= 0x7fffffff;
+  /* ix >= 0x40000000 for all calls to this function.  */
   if (ix >= 0x41b00000)
     {
       return one;
@@ -321,7 +322,7 @@ pzero (double x)
     {
       p = pR3; q = pS3;
     }
-  else if (ix >= 0x40000000)
+  else
     {
       p = pR2; q = pS2;
     }
@@ -423,6 +424,7 @@ qzero (double x)
   int32_t ix;
   GET_HIGH_WORD (ix, x);
   ix &= 0x7fffffff;
+  /* ix >= 0x40000000 for all calls to this function.  */
   if (ix >= 0x41b00000)
     {
       return -.125 / x;
@@ -439,7 +441,7 @@ qzero (double x)
     {
       p = qR3; q = qS3;
     }
-  else if (ix >= 0x40000000)
+  else
     {
       p = qR2; q = qS2;
     }
diff --git a/sysdeps/ieee754/dbl-64/e_j1.c b/sysdeps/ieee754/dbl-64/e_j1.c
index b7b8a9a..d61cff4 100644
--- a/sysdeps/ieee754/dbl-64/e_j1.c
+++ b/sysdeps/ieee754/dbl-64/e_j1.c
@@ -305,6 +305,7 @@ pone (double x)
   int32_t ix;
   GET_HIGH_WORD (ix, x);
   ix &= 0x7fffffff;
+  /* ix >= 0x40000000 for all calls to this function.  */
   if (ix >= 0x41b00000)
     {
       return one;
@@ -321,7 +322,7 @@ pone (double x)
     {
       p = pr3; q = ps3;
     }
-  else if (ix >= 0x40000000)
+  else
     {
       p = pr2; q = ps2;
     }
@@ -424,6 +425,7 @@ qone (double x)
   int32_t ix;
   GET_HIGH_WORD (ix, x);
   ix &= 0x7fffffff;
+  /* ix >= 0x40000000 for all calls to this function.  */
   if (ix >= 0x41b00000)
     {
       return .375 / x;
@@ -440,7 +442,7 @@ qone (double x)
     {
       p = qr3; q = qs3;
     }
-  else if (ix >= 0x40000000)
+  else
     {
       p = qr2; q = qs2;
     }
diff --git a/sysdeps/ieee754/flt-32/e_j0f.c b/sysdeps/ieee754/flt-32/e_j0f.c
index c4cabd5..bd0b80f 100644
--- a/sysdeps/ieee754/flt-32/e_j0f.c
+++ b/sysdeps/ieee754/flt-32/e_j0f.c
@@ -228,10 +228,11 @@ pzerof(float x)
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+	/* ix >= 0x40000000 for all calls to this function.  */
 	if(ix>=0x41000000)     {p = pR8; q= pS8;}
 	else if(ix>=0x40f71c58){p = pR5; q= pS5;}
 	else if(ix>=0x4036db68){p = pR3; q= pS3;}
-	else if(ix>=0x40000000){p = pR2; q= pS2;}
+	else {p = pR2; q= pS2;}
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*q[4]))));
@@ -324,10 +325,11 @@ qzerof(float x)
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+	/* ix >= 0x40000000 for all calls to this function.  */
 	if(ix>=0x41000000)     {p = qR8; q= qS8;}
 	else if(ix>=0x40f71c58){p = qR5; q= qS5;}
 	else if(ix>=0x4036db68){p = qR3; q= qS3;}
-	else if(ix>=0x40000000){p = qR2; q= qS2;}
+	else {p = qR2; q= qS2;}
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
diff --git a/sysdeps/ieee754/flt-32/e_j1f.c b/sysdeps/ieee754/flt-32/e_j1f.c
index 920e4b8..a67da32 100644
--- a/sysdeps/ieee754/flt-32/e_j1f.c
+++ b/sysdeps/ieee754/flt-32/e_j1f.c
@@ -230,10 +230,11 @@ ponef(float x)
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+	/* ix >= 0x40000000 for all calls to this function.  */
 	if(ix>=0x41000000)     {p = pr8; q= ps8;}
 	else if(ix>=0x40f71c58){p = pr5; q= ps5;}
 	else if(ix>=0x4036db68){p = pr3; q= ps3;}
-	else if(ix>=0x40000000){p = pr2; q= ps2;}
+	else {p = pr2; q= ps2;}
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*q[4]))));
@@ -327,10 +328,11 @@ qonef(float x)
 	int32_t ix;
 	GET_FLOAT_WORD(ix,x);
 	ix &= 0x7fffffff;
+	/* ix >= 0x40000000 for all calls to this function.  */
 	if(ix>=0x40200000)     {p = qr8; q= qs8;}
 	else if(ix>=0x40f71c58){p = qr5; q= qs5;}
 	else if(ix>=0x4036db68){p = qr3; q= qs3;}
-	else if(ix>=0x40000000){p = qr2; q= qs2;}
+	else {p = qr2; q= qs2;}
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
diff --git a/sysdeps/ieee754/ldbl-96/e_j0l.c b/sysdeps/ieee754/ldbl-96/e_j0l.c
index 56f48f1..a536054 100644
--- a/sysdeps/ieee754/ldbl-96/e_j0l.c
+++ b/sysdeps/ieee754/ldbl-96/e_j0l.c
@@ -356,6 +356,7 @@ pzero (long double x)
 
   GET_LDOUBLE_WORDS (se, i0, i1, x);
   ix = se & 0x7fff;
+  /* ix >= 0x4000 for all calls to this function.  */
   if (ix >= 0x4002)
     {
       p = pR8;
@@ -374,7 +375,7 @@ pzero (long double x)
 	  p = pR3;
 	  q = pS3;
 	}
-      else if (ix >= 0x4000)	/* x better be >= 2 */
+      else	/* x >= 2 */
 	{
 	  p = pR2;
 	  q = pS2;
@@ -493,6 +494,7 @@ qzero (long double x)
 
   GET_LDOUBLE_WORDS (se, i0, i1, x);
   ix = se & 0x7fff;
+  /* ix >= 0x4000 for all calls to this function.  */
   if (ix >= 0x4002)		/* x >= 8 */
     {
       p = qR8;
@@ -511,7 +513,7 @@ qzero (long double x)
 	  p = qR3;
 	  q = qS3;
 	}
-      else if (ix >= 0x4000)	/* x better be >= 2 */
+      else	/* x >= 2 */
 	{
 	  p = qR2;
 	  q = qS2;
diff --git a/sysdeps/ieee754/ldbl-96/e_j1l.c b/sysdeps/ieee754/ldbl-96/e_j1l.c
index 88fcf13..1adc8f6 100644
--- a/sysdeps/ieee754/ldbl-96/e_j1l.c
+++ b/sysdeps/ieee754/ldbl-96/e_j1l.c
@@ -359,6 +359,7 @@ pone (long double x)
 
   GET_LDOUBLE_WORDS (se, i0, i1, x);
   ix = se & 0x7fff;
+  /* ix >= 0x4000 for all calls to this function.  */
   if (ix >= 0x4002) /* x >= 8 */
     {
       p = pr8;
@@ -377,7 +378,7 @@ pone (long double x)
 	  p = pr3;
 	  q = ps3;
 	}
-      else if (ix >= 0x4000)	/* x better be >= 2 */
+      else	/* x >= 2 */
 	{
 	  p = pr2;
 	  q = ps2;
@@ -505,6 +506,7 @@ qone (long double x)
 
   GET_LDOUBLE_WORDS (se, i0, i1, x);
   ix = se & 0x7fff;
+  /* ix >= 0x4000 for all calls to this function.  */
   if (ix >= 0x4002)		/* x >= 8 */
     {
       p = qr8;
@@ -523,7 +525,7 @@ qone (long double x)
 	  p = qr3;
 	  q = qs3;
 	}
-      else if (ix >= 0x4000)	/* x better be >= 2 */
+      else	/* x >= 2 */
 	{
 	  p = qr2;
 	  q = qs2;

-- 
Joseph S. Myers
joseph@codesourcery.com


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