https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63281
Alan Modra <amodra at gmail dot com> changed:
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Attachment #33503|0 |1
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--- Comment #7 from Alan Modra <amodra at gmail dot com> ---
Created attachment 42186
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42186&action=edit
[RS6000] Cost multi-insn constants
I think the patches aren't worth pursuing *until* insn and rtl costing is
fixed. That's the really big problem, and I think fixing it will require
someone willing to regress things for a while on all targets. I looked at
doing that some years ago and came to the conclusion that I didn't have the
reputation in the gcc community for anything I did to be accepted.
Without fixed costing, even if we emit what we think is better code in
rs6000_emit_set_const, optimization passes may transform that code to
non-optimal sequences.
So, within the current broken rtx costing, the attached patch teaches gcc to
cost multi-insn constants.
