Any update? This is blocking a number of other R packages on ARM that all previously built fine

1.0.4.1 has the same bug, just not triggered by the less strict test.

bitflip(-1) should be 0, but on arm, it is 4294967295.

Something in this function is not correct on ARM:

SEXP bitFlip(SEXP a, SEXP bitWidth ) {
        int i, n, *xbitWidth;
        unsigned int  mask ;
        unsigned int tmp ;
        double *xa, *xaflip ;
        SEXP aflip ;

        PROTECT (a = AS_NUMERIC(a) ) ;
        PROTECT (bitWidth = AS_INTEGER(bitWidth) ) ;

        n=LENGTH(a) ;
        PROTECT (aflip = NEW_NUMERIC(n) ) ;

        xa=NUMERIC_POINTER(a) ;
        xaflip=NUMERIC_POINTER(aflip) ;
        xbitWidth=INTEGER_POINTER(bitWidth)  ;

        mask = ( unsigned int ) -1 >> (32 - *xbitWidth)  ;


        for (i=0; i<n; i++ ) {
                if ( !R_FINITE(xa[i]) || logb(xa[i])>31 ) xaflip[i]=NA_REAL ;

                else {
                      	tmp=(unsigned int) xa[i] ;
                        xaflip[i]=(double) ( ~tmp & mask ) ;
                }
        }
	UNPROTECT(3) ;
        return (aflip) ;
}

This is the bug:

                      	tmp=(unsigned int) xa[i] ;

Casting double to unsigned is undefined if the value is negative.

Use this instead:

                      	tmp=xa[i] < 0 ? (int) xa[i] : (unsigned) xa[i];

Here's a small reproducer if you want to play with it:

#include <stdio.h>

int
main(int argc, char **argv)
{
  double v = 0.0;
  sscanf(argv[1], "%lf", &v);
  unsigned i = (int) v;
  printf("int = %08x\n", i);
  unsigned u = (unsigned) v;
  printf("unsigned = %08x\n", u);
  return 0;
}

[root@calxeda-arm-soc-02 ~]# ./a.out -1
int = ffffffff
unsigned = 00000000

Thanks Florian! Fixed in R-bitops-1.0.5-3.fc20. Patch sent to upstream.