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authorjsm28 <jsm28@138bc75d-0d04-0410-961f-82ee72b054a4>2008-10-29 17:05:42 +0000
committerjsm28 <jsm28@138bc75d-0d04-0410-961f-82ee72b054a4>2008-10-29 17:05:42 +0000
commit02c52e944f67987d3e2a506e9e3e9c60282db7ae (patch)
treef0bc48b745fe374d4990579d0ef02a2d88bb7799 /gcc/real.c
parentb43b7954e03f8578e48822cd9b5753feae3ec616 (diff)
downloadgcc-02c52e944f67987d3e2a506e9e3e9c60282db7ae.tar.gz
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. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@141432 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/real.c')
-rw-r--r--gcc/real.c29
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. */