On 2015-07-16 22:29, Richard Henderson wrote: > On 07/15/2015 09:54 PM, Aurelien Jarno wrote: > >While I understand why we need the new trunc_shr_i32 opcode for MIPS64 > >(the 32-bit values must be kept sign-extended), I currently fail to > >see why it is needed for SPARC. > > As far as I recall, it improves code for extracting high parts of 64-bit > quantities. Without this, we wind up with a 64-bit shift, requiring a > 64-bit temp register, followed by the "real" truncate which can copy the > data to a 32-bit destination register.
Ok, I understand the use case now. So it's not for correctness, but rather to generate more optimized code. -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://www.aurel32.net
