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Ocamlopt code generator question
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Date: | 2009-05-05 (14:15) |
From: | Jean-Marc Eber <jeanmarc.eber@l...> |
Subject: | Re: [Caml-list] Ocamlopt code generator question |
Hi Dimitry, LexiFi for instance _is_ clearly interested by a sse2 32bit code generator. One should probably have the following in mind and/or ask the following questions: - it is probably not a good idea to support both backends (sse2 and old stack fp i386 architecture). It will be necessary to make a choice (especially taking in account the limited INRIA resources and the burden of already supporting different windows ports). - would INRIA be ok to switch to a sse2 code generator (based on Dimitry's patch - supposing that he is ok to donate it to INRIA - or Xavier's work or whatever)? - I also guess that a sse2 code generator would be simpler than the current one (that has to support this horrible fp stack architecture) and would therefore be a better candidate for further enhancements. - what is the opinion on this list, as a switch to a sse2 backend would exclude "old" processors from being OCaml compatible (I don't have a precise list at hand for now) ? My opinion is that this support of legacy hardware is not important, but I guess others are arguing in opposite directions... :-) But again, having better floating point performance (and predictable behaviour, compared to the bytecode version) would be a big plus for some applications. Best regards, Jean-Marc Dmitry Bely a écrit : > > I see. Why I asked this: trying to improve floating-point performance > on 32-bit x86 platform I have merged floating-point SSE2 code > generator from amd64 ocamlopt back end to i386 one, making ia32sse2 > architecture. It also inlines sqrt() via -ffast-math flag and slightly > optimizes emit_float_test (usually eliminates an extra jump) - > features that are missed in the original amd64 code generator. All > this seems to work OK: beyond my own code all tests found in Ocaml CVS > test directory are passed. Of course this is idea is not new - you had > working IA32+SSE2 back end several years ago [1] but unfortunately > never released it to the public. > > Is this of any interest to anybody? > > - Dmitry Bely > > [1] http://caml.inria.fr/pub/ml-archives/caml-list/2003/03/e0db2f3f54ce19e4bad589ffbb082484.fr.html > > _______________________________________________ > Caml-list mailing list. Subscription management: > http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list > Archives: http://caml.inria.fr > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners > Bug reports: http://caml.inria.fr/bin/caml-bugs