From 546b46c309a52ed74dc906114b1e984bb9703d74 Mon Sep 17 00:00:00 2001 From: Martin Jansa Date: Fri, 14 Sep 2018 23:23:03 +0000 Subject: [PATCH] sysdeps/ieee754: prevent maybe-uninitialized errors with -O [BZ #19444] With -O included in CFLAGS it fails to build with: ../sysdeps/ieee754/ldbl-96/e_jnl.c: In function '__ieee754_jnl': ../sysdeps/ieee754/ldbl-96/e_jnl.c:146:20: error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized] b = invsqrtpi * temp / sqrtl (x); ~~~~~~~~~~^~~~~~ ../sysdeps/ieee754/ldbl-96/e_jnl.c: In function '__ieee754_ynl': ../sysdeps/ieee754/ldbl-96/e_jnl.c:375:16: error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized] b = invsqrtpi * temp / sqrtl (x); ~~~~~~~~~~^~~~~~ ../sysdeps/ieee754/dbl-64/e_jn.c: In function '__ieee754_jn': ../sysdeps/ieee754/dbl-64/e_jn.c:113:20: error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized] b = invsqrtpi * temp / sqrt (x); ~~~~~~~~~~^~~~~~ ../sysdeps/ieee754/dbl-64/e_jn.c: In function '__ieee754_yn': ../sysdeps/ieee754/dbl-64/e_jn.c:320:16: error: 'temp' may be used uninitialized in this function [-Werror=maybe-uninitialized] b = invsqrtpi * temp / sqrt (x); ~~~~~~~~~~^~~~~~ Build tested with Yocto for ARM, AARCH64, X86, X86_64, PPC, MIPS, MIPS64 with -O, -O1, -Os. For soft-fp ARM it needs one more fix for -O1: https://sourceware.org/ml/libc-alpha/2018-09/msg00300.html For AARCH64 it needs one more fix in locale for -Os. [BZ #23716] * sysdeps/ieee754/dbl-96/e_jnl.c: Fix build with -O * sysdeps/ieee754/ldbl-96/e_jnl.c: Likewise. * sysdeps/ieee754/ldbl-128/e_jnl.c: Likewise. * sysdeps/ieee754/ldbl-128ibm/e_jnl.c: Likewise. Work around the issue instead of removing -O like we do with SELECTED_OPTIMIZATION Upstream-Status: Submitted [https://www.sourceware.org/ml/libc-alpha/2018-09/msg00299.html] Signed-off-by: Martin Jansa --- ChangeLog | 7 +++++++ sysdeps/ieee754/dbl-64/e_jn.c | 21 +++++++++++++++++++++ sysdeps/ieee754/ldbl-128/e_jnl.c | 21 +++++++++++++++++++++ sysdeps/ieee754/ldbl-128ibm/e_jnl.c | 21 +++++++++++++++++++++ sysdeps/ieee754/ldbl-96/e_jnl.c | 21 +++++++++++++++++++++ 5 files changed, 91 insertions(+) diff --git a/ChangeLog b/ChangeLog index 11a9b8d98e..922e916f2c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2018-09-29 Martin Jansa + Partial fix for [BZ #23716] + * sysdeps/ieee754/dbl-96/e_jnl.c: Fix build with -O + * sysdeps/ieee754/ldbl-96/e_jnl.c: Likewise. + * sysdeps/ieee754/ldbl-128/e_jnl.c: Likewise. + * sysdeps/ieee754/ldbl-128ibm/e_jnl.c: Likewise. + 2018-09-28 Adhemerval Zanella [BZ #23579] diff --git a/sysdeps/ieee754/dbl-64/e_jn.c b/sysdeps/ieee754/dbl-64/e_jn.c index 9181b22bb8..9ff52c737f 100644 --- a/sysdeps/ieee754/dbl-64/e_jn.c +++ b/sysdeps/ieee754/dbl-64/e_jn.c @@ -42,6 +42,7 @@ #include #include #include +#include static const double invsqrtpi = 5.64189583547756279280e-01, /* 0x3FE20DD7, 0x50429B6D */ @@ -109,7 +110,17 @@ __ieee754_jn (int n, double x) case 2: temp = -c - s; break; case 3: temp = c - s; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrt (x); + DIAG_POP_NEEDS_COMMENT; } else { @@ -316,7 +327,17 @@ __ieee754_yn (int n, double x) case 2: temp = -s + c; break; case 3: temp = s + c; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrt (x); + DIAG_POP_NEEDS_COMMENT; } else { diff --git a/sysdeps/ieee754/ldbl-128/e_jnl.c b/sysdeps/ieee754/ldbl-128/e_jnl.c index 7739eec291..8706a11575 100644 --- a/sysdeps/ieee754/ldbl-128/e_jnl.c +++ b/sysdeps/ieee754/ldbl-128/e_jnl.c @@ -61,6 +61,7 @@ #include #include #include +#include static const _Float128 invsqrtpi = L(5.6418958354775628694807945156077258584405E-1), @@ -150,7 +151,17 @@ __ieee754_jnl (int n, _Float128 x) temp = c - s; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrtl (x); + DIAG_POP_NEEDS_COMMENT; } else { @@ -386,7 +397,17 @@ __ieee754_ynl (int n, _Float128 x) temp = s + c; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrtl (x); + DIAG_POP_NEEDS_COMMENT; } else { diff --git a/sysdeps/ieee754/ldbl-128ibm/e_jnl.c b/sysdeps/ieee754/ldbl-128ibm/e_jnl.c index 71b3addfba..3226d02309 100644 --- a/sysdeps/ieee754/ldbl-128ibm/e_jnl.c +++ b/sysdeps/ieee754/ldbl-128ibm/e_jnl.c @@ -61,6 +61,7 @@ #include #include #include +#include static const long double invsqrtpi = 5.6418958354775628694807945156077258584405E-1L, @@ -150,7 +151,17 @@ __ieee754_jnl (int n, long double x) temp = c - s; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrtl (x); + DIAG_POP_NEEDS_COMMENT; } else { @@ -386,7 +397,17 @@ __ieee754_ynl (int n, long double x) temp = s + c; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrtl (x); + DIAG_POP_NEEDS_COMMENT; } else { diff --git a/sysdeps/ieee754/ldbl-96/e_jnl.c b/sysdeps/ieee754/ldbl-96/e_jnl.c index 394921f564..da5c2cc93e 100644 --- a/sysdeps/ieee754/ldbl-96/e_jnl.c +++ b/sysdeps/ieee754/ldbl-96/e_jnl.c @@ -61,6 +61,7 @@ #include #include #include +#include static const long double invsqrtpi = 5.64189583547756286948079e-1L, two = 2.0e0L, one = 1.0e0L; @@ -143,7 +144,17 @@ __ieee754_jnl (int n, long double x) temp = c - s; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrtl (x); + DIAG_POP_NEEDS_COMMENT; } else { @@ -372,7 +383,17 @@ __ieee754_ynl (int n, long double x) temp = s + c; break; } + /* With GCC 8 (and older) when compiling with -O the compiler + warns that the variable 'temp', may be used uninitialized. + The switch above covers all possible values of n & 3 + but GCC without VRP enabled isn't able to figure out the + range of possible values is [0,3] as explained in: + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69230 + so it's false possitive with -O1 and lower. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized"); b = invsqrtpi * temp / sqrtl (x); + DIAG_POP_NEEDS_COMMENT; } else {