[Bug target/104117] gcc10 fails to build icu for ppc64 on 10.5.8 (direct access to a floating-point constant)

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104117

--- Comment #2 from Iain Sandoe <iains at gcc dot gnu.org> ---
reduced testcase:

typedef int int32_t;
extern "C" {
extern double floor( double );
extern double fabs( double );
int atoi(const char *);
int sprintf(char * , const char * , ...) ;

}

namespace icu_67 {

class __attribute__((visibility("default"))) FixedDecimal {
  public:
    static int32_t decimals(double n);
};

//using namespace icu::pluralimpl;
//using icu::number::impl::DecimalQuantity;

static int32_t p10[] = {1, 10, 100, 1000, 10000};

int32_t FixedDecimal::decimals(double n) {


    n = fabs(n);
    for (int ndigits=0; ndigits<=3; ndigits++) {
        double scaledN = n * p10[ndigits];
        if (scaledN == floor(scaledN)) {
            return ndigits;
        }
    }


    char buf[30] = {0};
    sprintf(buf, "%1.15e", n);

    int exponent = atoi(buf+18);
    int numFractionDigits = 15;
    for (int i=16; ; --i) {
        if (buf[i] != '0') {
            break;
        }
        --numFractionDigits;
    }
    numFractionDigits -= exponent;
    return numFractionDigits;
}

}