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Fix sysdeps/ieee754/dbl-64/mpa.c for -Wuninitialized. 

If you remove the "override CFLAGS += -Wno-uninitialized" in
math/Makefile, one of the errors you get is:

../sysdeps/ieee754/dbl-64/mpa.c: In function '__mp_dbl.part.0':
../sysdeps/ieee754/dbl-64/mpa.c:183:5: error: 'c' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   c *= X[0];

The problem is that the p < 5 case initializes c if p is 1, 2, 3 or 4
but not otherwise, and in fact p is positive for all calls to this
function so the uninitialized case can't actually occur.  This patch
replaces the "if (p == 4)" last case with a comment so the compiler
can see that all paths do initialize c.

Tested for x86_64.

	* sysdeps/ieee754/dbl-64/mpa.c (norm): Remove if condition on
	(p == 4) case.
This commit is contained in:
Joseph Myers 2015-05-21 23:05:45 +00:00
parent 9d12d7652b
commit 89f3b6e18c
2 changed files with 6 additions and 2 deletions
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3
ChangeLog
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@ -1,5 +1,8 @@
2015-05-21 Joseph Myers <joseph@codesourcery.com> 2015-05-21 Joseph Myers <joseph@codesourcery.com>
* sysdeps/ieee754/dbl-64/mpa.c (norm): Remove if condition on
(p == 4) case.
* conform/linknamespace.pl (@whitelist): Add re_syntax_options. * conform/linknamespace.pl (@whitelist): Add re_syntax_options.
* conform/Makefile (test-xfail-UNIX98/regex.h/linknamespace): * conform/Makefile (test-xfail-UNIX98/regex.h/linknamespace):
Remove variable. Remove variable.

5
sysdeps/ieee754/dbl-64/mpa.c
View File

@ -119,7 +119,8 @@ __cpy (const mp_no *x, mp_no *y, int p)
#ifndef NO___MP_DBL #ifndef NO___MP_DBL
/* Convert a multiple precision number *X into a double precision /* Convert a multiple precision number *X into a double precision
number *Y, normalized case (|x| >= 2**(-1022))). */ number *Y, normalized case (|x| >= 2**(-1022))). X has precision
P, which is positive. */
static void static void
norm (const mp_no *x, double *y, int p) norm (const mp_no *x, double *y, int p)
{ {
@ -135,7 +136,7 @@ norm (const mp_no *x, double *y, int p)
c = X[1] + R * X[2]; c = X[1] + R * X[2];
else if (p == 3) else if (p == 3)
c = X[1] + R * (X[2] + R * X[3]); c = X[1] + R * (X[2] + R * X[3]);
else if (p == 4) else /* p == 4. */
c = (X[1] + R * X[2]) + R * R * (X[3] + R * X[4]); c = (X[1] + R * X[2]) + R * R * (X[3] + R * X[4]);
} }
else else