math: add fma TODO comments about the underflow issue

[oweals/musl.git] / src / math / ilogbf.c

diff --git a/src/math/ilogbf.c b/src/math/ilogbf.c
index 272cbdac0ccf36dc2bb9d2ede7116853cad1748f..42cd62e2dd9b37598c716b73825090fd74eb588a 100644 (file)
--- a/src/math/ilogbf.c
+++ b/src/math/ilogbf.c
@@ -8,13 +8,17 @@ int ilogbf(float x)
 
        if (!e) {
                u.bits <<= 9;
-               if (u.bits == 0)
+               if (u.bits == 0) {
+                       FORCE_EVAL(0/0.0f);
                        return FP_ILOGB0;
+               }
                /* subnormal x */
                for (e = -0x7f; u.bits < (uint32_t)1<<31; e--, u.bits<<=1);
                return e;
        }
-       if (e == 0xff)
+       if (e == 0xff) {
+               FORCE_EVAL(0/0.0f);
                return u.bits<<9 ? FP_ILOGBNAN : INT_MAX;
+       }
        return e - 0x7f;
 }