C++ compile-time regressions

Joe Buck jbuck@synopsys.COM
Thu Aug 2 12:37:00 GMT 2001

> >> But I wonder if the default value of PARAM_MAX_INLINE_INSNS should be
> >> a property of the target machine.  Different targets have different
> >> INSN densities.  I don't know how much this changes from one target to
> >> another in the early rtl stages used for rtl inlining, though...  Does
> >> anyone more experienced think it would be worth the trouble?  I could
> >> produce a patch to make the default target-modifiable.

> > I think we're tackling this from the wrong angle.

> I think I wasn't clear.  My suggestion didn't mean to affect compile
> time, but rather, to offer a reasonably similar behavior across
> multiple targets, in regards to inlining or not inlining functions.

But you're assuming that the current heuristic approach to inlining is
valid and only the parameter needs adjustment, and proposing a theory
about how it should be adjusted (normalize for instruction density)
without evidence that this is the right thing.

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