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Re: ACCUMULATE_OUTGOING_ARGS and the i386
- To: John Wehle <john at feith dot com>
- Subject: Re: ACCUMULATE_OUTGOING_ARGS and the i386
- From: John Carr <jfc at mit dot edu>
- Date: Mon, 19 Oct 1998 18:06:54 EDT
- Cc: egcs at cygnus dot com
> What are the tradeoffs involved in ACCUMULATE_OUTGOING_ARGS? Why
> would I not want to implement it for the i386? Does it impact debugging?
The Metaware compiler does the equivalent optimization for some x86
targets so it is probably reasonably safe and good.
On most x86 targets, ACCUMULATE_OUTGOING_ARGS generates faster, larger
code. A 1 byte push becomes a 5+ byte move.
The code size expansion can be significant, so I think we should first
change gcc to test the value ACCUMULATE_OUTGOING_ARGS at runtime.
On x86 it should be off for (at least) target=386 or flag_optimize_size.