libgcc: strange optimization

[Mikael Pettersson]

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.

/Mikael