How to diagnose inlining failure?

[Henrik Mannerström]

Hello,

I get the following warning from the compiler:

header.h:10: warning: inlining failed in call to ‘double hill(double,
double, double)Â’: call is unlikely and code size would grow

I know that the "--param" option has many variables controlling inlining
but I don't know which ones to change. Can I get some kind of diagnostic
of the specific decision the compiler makes when not inlining?

Thanks!
BR,
Henrik