Sorry for the noise, but the catanf.i.gz above was from a slightly modified
catanf.c (which had the same behavior as the original code).
I had changed this from upstream musl:
===
--- a/src/complex/catanf.c
+++ b/src/complex/catanf.c
@@ -61,12 +61,12 @@ static const double DP1 = 3.140625;
 static const double DP2 = 9.67502593994140625E-4;
 static const double DP3 = 1.509957990978376432E-7;
 
-static float _redupif(float xx)
+static float _redupif(float x)
 {
-	float x, t;
+	float t;
 	long i;
 
-	x = xx;
+	//x = xx;
 	t = x/(float)M_PI;
 	if (t >= 0.0f)
 		t += 0.5f;
===

The preprocessed code has a corresponding change; I'm attaching the gzip'd
result of the original code.

Thanks,
Isaac Dunham