http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48236
--- Comment #3 from Jon Valdes <juanval at gmail dot com> 2011-03-22 14:35:10 UTC --- >From my understanding, a positive number should be casted to exactly the same floating value representation regardless if the variable is signed or unsigned. In fact, checking the failing values, we see this: uint64_t ui: 16777217 -> (float) ui:16777216.000000 ( ui - 1 ) uint64_t ui: 16777218 -> (float) ui:16777218.000000 ( correct ) uint64_t ui: 16777219 -> (float) ui:16777220.000000 ( ui + 1 ) The casting of a uint64_t value to float wiggles around the correct value, but an int64_t value stays correct. int64_t i : 16777217 -> (float) i:16777217.000000 ( correct ) int64_t i : 16777218 -> (float) i:16777218.000000 ( correct ) int64_t i : 16777219 -> (float) i:16777219.000000 ( correct )
