On 01/07/11 14:30, Stubbs, Andrew wrote: >> Got it now! Casts from signed to unsigned are not value-preserving, but >> > they are "bit-preserving": s32->s64 obviously is, and s32->u64 has the >> > same result bit-by-bit as the s64 result. The fact that s64 has an >> > implicit 1111... in front, while an u64 has an implicit 0000... does not >> > matter. > But, the 1111... and 0000... are not implicit. They are very real, and > if applied incorrectly will change the result, I think.
Wait, I'm clearly confused .... When I try a s32->u64 conversion, the expand pass generates a sign_extend insn. Clearly it's the source type that determines the extension type, not the destination type ... and I'm a dunce! Thanks :) Andrew
