Re: [RS6000] num_insns_constant ICE

[Segher Boessenkool <segher at kernel dot crashing dot org>]

On Fri, Nov 30, 2018 at 06:16:40PM +1030, Alan Modra wrote:
> On Thu, Nov 29, 2018 at 01:52:34PM -0600, Segher Boessenkool wrote:
> > On Sun, Nov 25, 2018 at 10:49:12PM +1030, Alan Modra wrote:
> > > +  while (nregs-- > 0)
> > > +    {
> > > +      int ins = num_insns_constant_gpr (value);
> > 
> > You probably should mask "value" here so that it is only one GPR.
> > Alternatively, make num_insns_constant_gpr handle that.  Consider what
> > happens for a 64-bit number with 32-bit registers here?
> 
> Oh, right, the low part will always give an answer of 2 if the high
> parts isn't merely a sign extension.
> 
> > > +	    val = l[WORDS_BIG_ENDIAN ? 0 : 1] << 32;
> > 
> > This doesn't work, as in the other patch: long can be 32 bit.
> 
> Huh, I originally had "high" and "low" HOST_WIDE_INTs which avoided
> this sort of problem on 32-bit hosts.
> 
> Revised patch follows.  Bootstrapped and regression tested
> powerpc64le-linux.  Hopefully this has removed all the stupidity.

I think it is fine like this, or certainly an improvement :-)  Okay for
trunk.  Thanks!


Segher


> 	* config/rs6000/rs6000.c (num_insns_constant_gpr): Renamed from
> 	num_insns_constant_wide.  Make static.  Revise comment.
> 	(num_insns_constant_multi): New function.
> 	(num_insns_constant): Formatting.  Correct CONST_WIDE_INT
> 	calculation.  Simplify and extract code common to both
> 	CONST_INT and CONST_DOUBLE.  Add gcc_unreachable for unhandled
> 	const_double modes.
> 	* config/rs6000/rs6000-protos.h (num_insns_const_wide): Delete.