[PATCH] D49514: [compiler-rt] [builtins] Add logb/logbf/logbl methods to compiler-rt to avoid libm dependencies when possible.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Maybe just make this a static inline function in fp_lib.h?

Maybe worth implementing something like ilogb instead, to avoid an extra int->float->int conversion?  I guess it's not that important.

> Fixes PR32279 and PR28652.

Is this really enough to fix PR32279?  That report mentions some other symbols (scalbn*, fmaxl).



================
Comment at: lib/builtins/ppc/divtc3.c:26
 	int ilogbw = 0;
-	const double logbw = crt_logb(crt_fmax(crt_fabs(cDD.s.hi), crt_fabs(dDD.s.hi) ));
-	
-	if (crt_isfinite(logbw))
+	const double logbw = __compiler_rt_logbl(
+		crt_fmax(crt_fabs(cDD.s.hi), crt_fabs(dDD.s.hi)));
----------------
This is wrong. The original code is calling logb, not logbl.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D49514