From 9124ccf76abc5a2ffe4603e6424b1dc2b5a5db44 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Thu, 21 May 2015 23:44:33 +0000 Subject: Fix lgamma implementations for -Wuninitialized. If you remove the "override CFLAGS += -Wno-uninitialized" in math/Makefile, you get errors from lgamma implementations of the form: ../sysdeps/ieee754/dbl-64/e_lgamma_r.c: In function '__ieee754_lgamma_r': ../sysdeps/ieee754/dbl-64/e_lgamma_r.c:297:13: error: 'nadj' may be used uninitialized in this function [-Werror=maybe-uninitialized] if(hx<0) r = nadj - r; This is one of the standard kinds of false positive uninitialized warnings: nadj is set under a certain condition, and then later used under the same condition. This patch uses DIAG_* macros to suppress the warning on the use of nadj. The ldbl-128 / ldbl-128ibm implementation has a substantially different structure that avoids this issue. Tested for x86_64. (In fact this patch eliminates the need for that -Wno-uninitialized on x86_64, but I want to test on more architectures before removing it.) * sysdeps/ieee754/dbl-64/e_lgamma_r.c: Include . (__ieee754_lgamma_r): Ignore uninitialized warnings around use of NADJ. * sysdeps/ieee754/flt-32/e_lgammaf_r.c: Include . (__ieee754_lgammaf_r): Ignore uninitialized warnings around use of NADJ. * sysdeps/ieee754/ldbl-96/e_lgammal_r.c: Include . (__ieee754_lgammal_r): Ignore uninitialized warnings around use of NADJ. --- sysdeps/ieee754/flt-32/e_lgammaf_r.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'sysdeps/ieee754/flt-32/e_lgammaf_r.c') diff --git a/sysdeps/ieee754/flt-32/e_lgammaf_r.c b/sysdeps/ieee754/flt-32/e_lgammaf_r.c index 4743bee438..c0bf4156ff 100644 --- a/sysdeps/ieee754/flt-32/e_lgammaf_r.c +++ b/sysdeps/ieee754/flt-32/e_lgammaf_r.c @@ -13,6 +13,7 @@ * ==================================================== */ +#include #include #include @@ -229,7 +230,18 @@ __ieee754_lgammaf_r(float x, int *signgamp) } else /* 2**26 <= x <= inf */ r = x*(__ieee754_logf(x)-one); + /* NADJ is set for negative arguments but not otherwise, + resulting in warnings that it may be used uninitialized + although in the cases where it is used it has always been + set. */ + DIAG_PUSH_NEEDS_COMMENT; +#if __GNUC_PREREQ (4, 7) + DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized"); +#else + DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wuninitialized"); +#endif if(hx<0) r = nadj - r; + DIAG_POP_NEEDS_COMMENT; return r; } strong_alias (__ieee754_lgammaf_r, __lgammaf_r_finite) -- cgit 1.4.1