Richard Guenther wrote: > On Tue, Aug 2, 2011 at 10:48 AM, Mikael Pettersson <mi...@it.uu.se> wrote: >> Hans-Peter Nilsson writes: >> > On Mon, 1 Aug 2011, Richard Henderson wrote: >> > >> > > On 08/01/2011 01:30 PM, Michael Walle wrote: >> > > > 1) function inlining >> > > > 2) deferred argument evaluation >> > > > 3) because our target has no barrel shifter, (arg >> 10) is emitted >> as a >> > > > function call to libgcc's __ashrsi3 (_in place_!) >> > > > 4) BAM! dead code elimination optimizes r8 assignment away because >> calli >> > > > may clobber r1-r10 (callee saved registers on lm32). >> > > >> > > I'm afraid the only solution I can think of is to force F1 out-of-line. >> > >> > Or another temporary - but the parameter should already have >> > that effect. >> >> It should, but doesn't. See PR48863 for similar breakage on ARM. > > On GIMPLE we don't see either the libcall nor those "dependencies". > > Don't use register vars.
IMO such code is supposed to work, e.g. in order to write an interface to a non-ABI assembler function. In general this cannot be expressed by means of constraints because that would imply plethora of different constraints for each register/mode. >From the documentation a user will expect that he wrote correct code and is not supposed to bother with GCC inerts like implicit library calls or GIMPLE or whatever. Johann > Richard.
