[compiler-rt] [builtins] Fix logb / logbl tests

[luismarques]

Summary

Like was done before in D67999 for logbf, this patch fixes the tests for the internal compiler-rt implementations of logb and logbl to consider all NaNs equivalent. Not doing so was resulting in test failures for riscv64, since the the NaNs had different signs, but the spec doesn't specify the NaN signedness or payload.

The patch also fixes the test failure error message for logbl: the incorrect function name, and the %a format not being applicable to format the long double.

This addresses bug 44244 (https://bugs.llvm.org/show_bug.cgi?id=44244).

[delcypher]

LGTM.

[rupprecht]

Thanks!

compiler-rt/test/builtins/Unit/compiler_rt_logb_test.c

 #define DOUBLE_PRECISION
 #include <math.h>
 #include <stdio.h>
 #include "fp_lib.h"
 
 int test__compiler_rt_logb(fp_t x) {
   fp_t crt_value = __compiler_rt_logb(x);
   fp_t libm_value = logb(x);
-  // Compare actual rep, e.g. to avoid NaN != the same NaN
-  if (toRep(crt_value) != toRep(libm_value)) {
+  // Compare the values, considering all NaNs equivalent, as the spec doesn't
+  // specify the NaN signedness/payload.
+  if (crt_value != libm_value &&
+      !(crt_isnan(crt_value) && crt_isnan(libm_value))) {
     printf("error: in __compiler_rt_logb(%a [%lX]) = %a [%lX] !=  %a [%lX]\n",
            x, toRep(x), crt_value, toRep(crt_value), libm_value,
            toRep(libm_value));
     return 1;
   }
   return 0;
 }
 

compiler-rt/test/builtins/Unit/compiler_rt_logbl_test.c

 #include "fp_lib.h"
 #include "int_lib.h"
 
 #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
 
 int test__compiler_rt_logbl(fp_t x) {
   fp_t crt_value = __compiler_rt_logbl(x);
   fp_t libm_value = logbl(x);
-  // Compare actual rep, e.g. to avoid NaN != the same NaN
-  if (toRep(crt_value) != toRep(libm_value)) {
+  // Compare the values, considering all NaNs equivalent, as the spec doesn't
+  // specify the NaN signedness/payload.
+  if (crt_value != libm_value &&
+      !(crt_isnan(crt_value) && crt_isnan(libm_value))) {
     // Split expected values into two for printf
     twords x_t, crt_value_t, libm_value_t;
     x_t.all = toRep(x);
     crt_value_t.all = toRep(crt_value);
     libm_value_t.all = toRep(libm_value);
     printf(
-        "error: in __compiler_rt_logb(%a [%llX %llX]) = %a [%llX %llX] !=  %a "
+        "error: in __compiler_rt_logbl([%llX %llX]) = [%llX %llX] !=  "
         "[%llX %llX]\n",
-        x, x_t.s.high, x_t.s.low, crt_value, crt_value_t.s.high,
-        crt_value_t.s.low, libm_value, libm_value_t.s.high, libm_value_t.s.low);
+        x_t.s.high, x_t.s.low, crt_value_t.s.high, crt_value_t.s.low,
+        libm_value_t.s.high, libm_value_t.s.low);
     return 1;
   }
   return 0;
 }
 
 double cases[] = {
     1.e-6, -1.e-6, NAN, -NAN, INFINITY, -INFINITY, -1,
     -0.0,  0.0,    1,   -2,   2,        -0.5,      0.5,