patch to omit the frame pointer from leaf functions

John Wehle john@feith.com
Mon Sep 21 11:04:00 GMT 1998


> Yes.  Without a fame pointer, debugging is usually impossible.
> On those targets where it is possible, you can set CAN_DEBUG_WITHOUT_FP and
> gcc will default to -fomit-frame-pointer when optimizing.

I believe that -fomit-frame-pointer is sometimes a performance loss on
non-leaf functions.  It's true that debugging becomes more difficult,
which is why my change only takes effect if optimize is not zero.
Perhaps it should only take effect if optimize >= 2.

Actually what I'm wondering is if there's ever a performance loss when
omitting the frame pointer in a leaf function.  On the i386 Intel
recommends always omitting the frame pointer in leaf functions.

-- John
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