diff options
Diffstat (limited to 'gcc/real.c')
| -rw-r--r-- | gcc/real.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/gcc/real.c b/gcc/real.c index dc6d7483e99..c5a16a867e1 100644 --- a/gcc/real.c +++ b/gcc/real.c @@ -1266,6 +1266,35 @@ exact_real_inverse (enum machine_mode mode, REAL_VALUE_TYPE *r) *r = u; return true; } + +/* Return true if arithmetic on values in IMODE that were promoted + from values in TMODE is equivalent to direct arithmetic on values + in TMODE. */ + +bool +real_can_shorten_arithmetic (enum machine_mode imode, enum machine_mode tmode) +{ + const struct real_format *tfmt, *ifmt; + tfmt = REAL_MODE_FORMAT (tmode); + ifmt = REAL_MODE_FORMAT (imode); + /* These conditions are conservative rather than trying to catch the + exact boundary conditions; the main case to allow is IEEE float + and double. */ + return (ifmt->b == tfmt->b + && ifmt->p > 2 * tfmt->p + && ifmt->emin < 2 * tfmt->emin - tfmt->p - 2 + && ifmt->emin < tfmt->emin - tfmt->emax - tfmt->p - 2 + && ifmt->emax > 2 * tfmt->emax + 2 + && ifmt->emax > tfmt->emax - tfmt->emin + tfmt->p + 2 + && ifmt->round_towards_zero == tfmt->round_towards_zero + && (ifmt->has_sign_dependent_rounding + == tfmt->has_sign_dependent_rounding) + && ifmt->has_nans >= tfmt->has_nans + && ifmt->has_inf >= tfmt->has_inf + && ifmt->has_signed_zero >= tfmt->has_signed_zero + && !MODE_COMPOSITE_P (tmode) + && !MODE_COMPOSITE_P (imode)); +} /* Render R as an integer. */ |