From a4f2895465da4c8856b119a5787b95db345567a9 Mon Sep 17 00:00:00 2001 From: Martin Liska Date: Fri, 2 Dec 2016 09:36:01 +0100 Subject: [PATCH] Fix runtime error: left shift of negative value (PR PR ipa/78555 * sreal.c (sreal::to_int): Make absolute value before shifting. (sreal::operator/): Likewise. (sreal_verify_negative_division): New test. (void sreal_c_tests): Call the new test. * sreal.h (sreal::normalize_up): Use new SREAL_ABS and SREAL_SIGN macros. (sreal::normalize_down): Likewise. From-SVN: r243163 --- gcc/ChangeLog | 11 +++++++++++ gcc/sreal.c | 20 +++++++++++++++++--- gcc/sreal.h | 9 +++++---- 3 files changed, 33 insertions(+), 7 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a3fcd8b6d0b..445384226cc 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +2016-12-02 Martin Liska + + PR ipa/78555 + * sreal.c (sreal::to_int): Make absolute value before shifting. + (sreal::operator/): Likewise. + (sreal_verify_negative_division): New test. + (void sreal_c_tests): Call the new test. + * sreal.h (sreal::normalize_up): Use new SREAL_ABS and + SREAL_SIGN macros. + (sreal::normalize_down): Likewise. + 2016-12-02 Dominik Vogt * combine.c (combine_simplify_rtx): Suppress replacement of diff --git a/gcc/sreal.c b/gcc/sreal.c index 9c43b4eed21..52e530d623f 100644 --- a/gcc/sreal.c +++ b/gcc/sreal.c @@ -102,14 +102,14 @@ sreal::shift_right (int s) int64_t sreal::to_int () const { - int64_t sign = m_sig < 0 ? -1 : 1; + int64_t sign = SREAL_SIGN (m_sig); if (m_exp <= -SREAL_BITS) return 0; if (m_exp >= SREAL_PART_BITS) return sign * INTTYPE_MAXIMUM (int64_t); if (m_exp > 0) - return m_sig << m_exp; + return sign * (SREAL_ABS (m_sig) << m_exp); if (m_exp < 0) return m_sig >> -m_exp; return m_sig; @@ -229,7 +229,8 @@ sreal::operator/ (const sreal &other) const { gcc_checking_assert (other.m_sig != 0); sreal r; - r.m_sig = (m_sig << SREAL_PART_BITS) / other.m_sig; + r.m_sig + = SREAL_SIGN (m_sig) * (SREAL_ABS (m_sig) << SREAL_PART_BITS) / other.m_sig; r.m_exp = m_exp - other.m_exp - SREAL_PART_BITS; r.normalize (); return r; @@ -334,6 +335,18 @@ sreal_verify_shifting (void) verify_shifting (values[i]); } +/* Verify division by (of) a negative value. */ + +static void +sreal_verify_negative_division (void) +{ + ASSERT_EQ (sreal (1) / sreal (1), sreal (1)); + ASSERT_EQ (sreal (-1) / sreal (-1), sreal (1)); + ASSERT_EQ (sreal (-1234567) / sreal (-1234567), sreal (1)); + ASSERT_EQ (sreal (-1234567) / sreal (1234567), sreal (-1)); + ASSERT_EQ (sreal (1234567) / sreal (-1234567), sreal (-1)); +} + /* Run all of the selftests within this file. */ void sreal_c_tests () @@ -341,6 +354,7 @@ void sreal_c_tests () sreal_verify_basics (); sreal_verify_arithmetics (); sreal_verify_shifting (); + sreal_verify_negative_division (); } } // namespace selftest diff --git a/gcc/sreal.h b/gcc/sreal.h index ce9cdbbfded..21f14b01821 100644 --- a/gcc/sreal.h +++ b/gcc/sreal.h @@ -31,6 +31,9 @@ along with GCC; see the file COPYING3. If not see #define SREAL_BITS SREAL_PART_BITS +#define SREAL_SIGN(v) (v < 0 ? -1: 1) +#define SREAL_ABS(v) (v < 0 ? -v: v) + /* Structure for holding a simple real number. */ class sreal { @@ -193,7 +196,6 @@ inline sreal operator>> (const sreal &a, int exp) inline void sreal::normalize_up () { - int64_t s = m_sig < 0 ? -1 : 1; unsigned HOST_WIDE_INT sig = absu_hwi (m_sig); int shift = SREAL_PART_BITS - 2 - floor_log2 (sig); @@ -208,7 +210,7 @@ sreal::normalize_up () m_exp = -SREAL_MAX_EXP; sig = 0; } - if (s == -1) + if (SREAL_SIGN (m_sig) == -1) m_sig = -sig; else m_sig = sig; @@ -221,7 +223,6 @@ sreal::normalize_up () inline void sreal::normalize_down () { - int64_t s = m_sig < 0 ? -1 : 1; int last_bit; unsigned HOST_WIDE_INT sig = absu_hwi (m_sig); int shift = floor_log2 (sig) - SREAL_PART_BITS + 2; @@ -246,7 +247,7 @@ sreal::normalize_down () m_exp = SREAL_MAX_EXP; sig = SREAL_MAX_SIG; } - if (s == -1) + if (SREAL_SIGN (m_sig) == -1) m_sig = -sig; else m_sig = sig; -- 2.30.2