tests/fp: Explicitly set 2-NaN propagation rule

Explicitly set a 2-NaN propagation rule in the softfloat tests.  In
meson.build we put -DTARGET_ARM in fpcflags, and so we should select
here the Arm propagation rule of float_2nan_prop_s_ab.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241025141254.2141506-3-peter.maydell@linaro.org

tests/fp/fp-bench.c

@@ -488,6 +488,8 @@ static void run_bench(void)
 {
     bench_func_t f;
 
+    set_float_2nan_prop_rule(float_2nan_prop_s_ab, &soft_status);
+
     f = bench_funcs[operation][precision];
     g_assert(f);
     f();

tests/fp/fp-test-log2.c

@@ -70,6 +70,7 @@ int main(int ac, char **av)
     float_status qsf = {0};
     int i;
 
+    set_float_2nan_prop_rule(float_2nan_prop_s_ab, &qsf);
     set_float_rounding_mode(float_round_nearest_even, &qsf);
 
     test.d = 0.0;

tests/fp/fp-test.c

@@ -935,6 +935,8 @@ void run_test(void)
 {
     unsigned int i;
 
+    set_float_2nan_prop_rule(float_2nan_prop_s_ab, &qsf);
+
     genCases_setLevel(test_level);
     verCases_maxErrorCount = n_max_errors;