On Wed, 2 Aug 2017, Jeff Law wrote: > I think Joseph's suggestion for looking at partial float handling may be > useful, though ia64's RFmode may be more interesting as it's not a > multiple of 8 in bitsize. IF/KF modes on the ppc port have similar > properties.
The key issue those floating-point modes engage is the meaning of precision. IFmode and KFmode have precision set to 106 and 113 to distinguish them. But that's precision in the sense of number of mantissa bits; as normally understood in GCC, precision should be the number of significant bits, so 128 for both those modes (but having multiple different binary floating-point modes with the same precision would require changing how we deal with laying out long double, so the target specifies a mode for floating-point types rather than leaving it to be deduced from values such as LONG_DOUBLE_TYPE_SIZE). -- Joseph S. Myers jos...@codesourcery.com
