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Fixed renormalization in fp.mul. Relates to #872.

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This commit is contained in:
Christoph M. Wintersteiger 2017-07-31 18:34:46 +01:00
parent 175f042db8
commit a59907170d
2 changed files with 7 additions and 3 deletions
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8
src/ast/fpa/fpa2bv_converter.cpp
View file

@ -1598,7 +1598,7 @@ void fpa2bv_converter::mk_fma(func_decl * f, unsigned num, expr * const * args,
alignment_sticky_raw = m_bv_util.mk_extract(sbits-1, 0, shifted_big); alignment_sticky_raw = m_bv_util.mk_extract(sbits-1, 0, shifted_big);
alignment_sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, alignment_sticky_raw.get()); alignment_sticky = m.mk_app(m_bv_util.get_fid(), OP_BREDOR, alignment_sticky_raw.get());
dbg_decouple("fpa2bv_fma_shifted_f_sig", shifted_f_sig); dbg_decouple("fpa2bv_fma_shifted_f_sig", shifted_f_sig);
dbg_decouple("fpa2bv_fma_f_sig_alignment_stickyw", alignment_sticky); dbg_decouple("fpa2bv_fma_f_sig_alignment_sticky", alignment_sticky);
SASSERT(is_well_sorted(m, alignment_sticky)); SASSERT(is_well_sorted(m, alignment_sticky));
SASSERT(m_bv_util.get_bv_size(shifted_f_sig) == 2 * sbits); SASSERT(m_bv_util.get_bv_size(shifted_f_sig) == 2 * sbits);
SASSERT(is_well_sorted(m, shifted_f_sig)); SASSERT(is_well_sorted(m, shifted_f_sig));
@ -1677,7 +1677,8 @@ void fpa2bv_converter::mk_fma(func_decl * f, unsigned num, expr * const * args,
// Renormalize // Renormalize
expr_ref zero_e2(m), min_exp(m), sig_lz(m), max_exp_delta(m), sig_lz_capped(m), renorm_delta(m); expr_ref zero_e2(m), min_exp(m), sig_lz(m), max_exp_delta(m), sig_lz_capped(m), renorm_delta(m);
zero_e2 = m_bv_util.mk_numeral(0, ebits + 2); zero_e2 = m_bv_util.mk_numeral(0, ebits + 2);
mk_min_exp(ebits+2, min_exp); mk_min_exp(ebits, min_exp);
min_exp = m_bv_util.mk_sign_extend(2, min_exp);
mk_leading_zeros(sig_abs, ebits+2, sig_lz); mk_leading_zeros(sig_abs, ebits+2, sig_lz);
sig_lz = m_bv_util.mk_bv_sub(sig_lz, m_bv_util.mk_numeral(2, ebits+2)); sig_lz = m_bv_util.mk_bv_sub(sig_lz, m_bv_util.mk_numeral(2, ebits+2));
max_exp_delta = m_bv_util.mk_bv_sub(res_exp, min_exp); max_exp_delta = m_bv_util.mk_bv_sub(res_exp, min_exp);
@ -1685,7 +1686,10 @@ void fpa2bv_converter::mk_fma(func_decl * f, unsigned num, expr * const * args,
renorm_delta = m.mk_ite(m_bv_util.mk_sle(zero_e2, sig_lz_capped), sig_lz_capped, zero_e2); renorm_delta = m.mk_ite(m_bv_util.mk_sle(zero_e2, sig_lz_capped), sig_lz_capped, zero_e2);
res_exp = m_bv_util.mk_bv_sub(res_exp, renorm_delta); res_exp = m_bv_util.mk_bv_sub(res_exp, renorm_delta);
sig_abs = m_bv_util.mk_bv_shl(sig_abs, m_bv_util.mk_zero_extend(2*sbits-ebits, renorm_delta)); sig_abs = m_bv_util.mk_bv_shl(sig_abs, m_bv_util.mk_zero_extend(2*sbits-ebits, renorm_delta));
dbg_decouple("fpa2bv_fma_min_exp", min_exp);
dbg_decouple("fpa2bv_fma_max_exp_delta", max_exp_delta);
dbg_decouple("fpa2bv_fma_sig_lz", sig_lz); dbg_decouple("fpa2bv_fma_sig_lz", sig_lz);
dbg_decouple("fpa2bv_fma_sig_lz_capped", sig_lz_capped);
dbg_decouple("fpa2bv_fma_renorm_delta", renorm_delta); dbg_decouple("fpa2bv_fma_renorm_delta", renorm_delta);
unsigned too_short = 0; unsigned too_short = 0;

2
src/util/mpf.cpp
View file

@ -919,7 +919,7 @@ void mpf_manager::fma(mpf_rounding_mode rm, mpf const & x, mpf const & y, mpf co
mpf_exp_t min_exp = mk_min_exp(x.ebits); mpf_exp_t min_exp = mk_min_exp(x.ebits);
unsigned sig_width = m_mpz_manager.prev_power_of_two(res.get().significand) + 1; unsigned sig_width = m_mpz_manager.prev_power_of_two(res.get().significand) + 1;
mpf_exp_t sig_lz = 2 * x.sbits - sig_width; // want << lz mpf_exp_t sig_lz = 2 * x.sbits - sig_width;
mpf_exp_t max_exp_delta = res.exponent() - min_exp; mpf_exp_t max_exp_delta = res.exponent() - min_exp;
unsigned renorm_delta = (unsigned) std::max((mpf_exp_t)0, std::min(sig_lz, max_exp_delta)); unsigned renorm_delta = (unsigned) std::max((mpf_exp_t)0, std::min(sig_lz, max_exp_delta));
res.get().exponent -= renorm_delta; res.get().exponent -= renorm_delta;