On 05/12/2018 01:35 PM, Bernd Schmidt wrote: > On 05/12/2018 07:01 PM, Jeff Law wrote: > >> No. We're not supposed to have any auto-inc insns prior to the auto-inc >> pass. A stack push/pop early in the compiler would have to be >> represented by a PARALLEL. >> >> It's been this way forever. It's documented in the internals manual >> somewhere. > > Sorry, but you're misremembering this. Stack pushes/pops were always > represented with autoinc, these being the only exception to the rule you > remember. You can easily verify this by looking at a .expand dump from a > 32-bit i386 compiler - I just did so with 2.95 and 6.4. It's all pre_dec > for argument passing. That does sound vaguely familiar. Did we put autoinc notes on the stack pushes?
That makes me wonder if there is a latent bug though. Consider pushing args to a pure function. Could we then try to CSE the memory reference and get it wrong because we haven't accounted for the autoinc? Jeff
