From 4a06ceea33ecc220bbfe264d8f1e74de2f04e90d Mon Sep 17 00:00:00 2001 From: Martin Jansa Date: Tue, 2 Oct 2018 15:38:43 +0000 Subject: [PATCH] sysdeps/ieee754/soft-fp: ignore maybe-uninitialized with -O [BZ #19444] * with -O, -O1, -Os it fails with: In file included from ../soft-fp/soft-fp.h:318, from ../sysdeps/ieee754/soft-fp/s_fdiv.c:28: ../sysdeps/ieee754/soft-fp/s_fdiv.c: In function '__fdiv': ../soft-fp/op-2.h:98:25: error: 'R_f1' may be used uninitialized in this function [-Werror=maybe-uninitialized] X##_f0 = (X##_f1 << (_FP_W_TYPE_SIZE - (N)) | X##_f0 >> (N) \ ^~ ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f1' was declared here FP_DECL_D (R); ^ ../soft-fp/op-2.h:37:36: note: in definition of macro '_FP_FRAC_DECL_2' _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT ^ ../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL' # define FP_DECL_D(X) _FP_DECL (2, X) ^~~~~~~~ ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D' FP_DECL_D (R); ^~~~~~~~~ ../soft-fp/op-2.h:101:17: error: 'R_f0' may be used uninitialized in this function [-Werror=maybe-uninitialized] : (X##_f0 << (_FP_W_TYPE_SIZE - (N))) != 0)); \ ^~ ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f0' was declared here FP_DECL_D (R); ^ ../soft-fp/op-2.h:37:14: note: in definition of macro '_FP_FRAC_DECL_2' _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT ^ ../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL' # define FP_DECL_D(X) _FP_DECL (2, X) ^~~~~~~~ ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D' FP_DECL_D (R); ^~~~~~~~~ Build tested with Yocto for ARM, AARCH64, X86, X86_64, PPC, MIPS, MIPS64 with -O, -O1, -Os. For AARCH64 it needs one more fix in locale for -Os. [BZ #19444] * sysdeps/ieee754/soft-fp/s_fdiv.c: Include and use DIAG_PUSH_NEEDS_COMMENT, DIAG_IGNORE_NEEDS_COMMENT and DIAG_POP_NEEDS_COMMENT to disable -Wmaybe-uninitialized. Signed-off-by: Yegor Yefremov --- sysdeps/ieee754/soft-fp/s_fdiv.c | 12 ++++++++++++ 1 files changed, 12 insertions(+) diff --git a/sysdeps/ieee754/soft-fp/s_fdiv.c b/sysdeps/ieee754/soft-fp/s_fdiv.c index 341339f5ed..7a15cbeee6 100644 --- a/sysdeps/ieee754/soft-fp/s_fdiv.c +++ b/sysdeps/ieee754/soft-fp/s_fdiv.c @@ -25,6 +25,16 @@ #undef fdivl #include +#include + +/* R_f[01] are not set in cases where they are not used in packing, + but the compiler does not see that they are set in all cases where + they are used, resulting in warnings that they may be used + uninitialized. The location of the warning differs in different + versions of GCC, it may be where R is defined using a macro or it + may be where the macro is defined. This happens only with -O1. */ +DIAG_PUSH_NEEDS_COMMENT; +DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); #include #include #include @@ -53,4 +63,6 @@ __fdiv (double x, double y) CHECK_NARROW_DIV (ret, x, y); return ret; } +DIAG_POP_NEEDS_COMMENT; + libm_alias_float_double (div) -- 2.17.0