From 20ded7a68b10f9c2d1aaa94e89df494bf0ce41a0 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 29 Oct 2008 17:05:42 +0000 Subject: re PR middle-end/36578 (cast to long double not taken into account when result stored to a double) PR middle-end/36578 * convert.c (convert_to_real): Do not optimize conversions of binary arithmetic operations between binary and decimal floating-point types. Consider mode of target type in determining decimal type for arithmetic. Unless flag_unsafe_math_optimizations, do not optimize binary conversions where this may change rounding behavior. * real.c (real_can_shorten_arithmetic): New. * real.h (real_can_shorten_arithmetic): Declare. testsuite: * gcc.dg/dfp/convert-bfp-13.c, gcc.dg/dfp/convert-bfp-14.c, gcc.dg/dfp/convert-dfp-fold-2.c, gcc.target/i386/pr36578-1.c, gcc.target/i386/pr36578-2.c: New tests. From-SVN: r141432 --- gcc/real.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'gcc/real.c') diff --git a/gcc/real.c b/gcc/real.c index dc6d748..c5a16a8 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. */ -- cgit v1.1