On 06/20/2016 07:40 PM, Andrew Haley wrote: > On 20/06/16 18:36, Michael Matz wrote: >> I see zero gain by deprecating them and only churn. What would be the >> advantage again? > > Correctness. It is very likely that many of these basic asms are not > robust in the face of compiler changes because they don't declare > their dependencies and therefore work only by accident.
But the correctness problem is much more severe with extended asm. With basic asm, the compiler can be conservative. With extended asm, there is an expectation that it is not, and yet many of the constraints out there are slightly wrong and can lead to breakage any time. Florian