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Re: [avr-llvm-devel] Inline assembly.
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From: Stepan D. <stp...@na...> - 2013-07-24 15:58:57
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Borja Ferrer wrote: > 1) I agree. > 3) What happens when you use multibyte constraints with "e" or "b". Just had checked it. It works :-) Though I'll add test-cases for them too. > 4) Hah ok, btw no need to check for i64? In one of our previous mails we decided to restrict i64 usage, since avr-gcc doesn't support it properly. -Stepan > > > 2013/7/24 Stepan Dyatkovskiy <stp...@na... <mailto:stp...@na...>> > > Hi Borja, > > > > 1) You implemented the "aN" constraint by also allowing b,c,d > > constraints. I'm not sure if gcc implements this, my guess is > that only > > "a" is needed. Please check to see what gcc does here. > > For b,c,d avr-gcc acts like it meet %a. I think its wrong and > untested behaviour, so I just restricted usage to single 'a' character. > > > > 2) Make getAlternativeRegName return a char instead of a string > since we > > only need to return one letter. > > Done > > > > 3) Related to the changes in AVRISelLowering.cpp, do we need to care > > about more register constraints apart of the ones you already > covered? > > What you mean? I think all constraints are covered now. If no, we > can find out it during compilation (avr-libc, arduino, etc). > > > > 4) Now that wider types have been covered, please check if the > assert I > > commented out in AVRISelLowering.cpp in the inline asm code can be > > removed or what. > > I replaced this assertion with error message. Suppose its better > than killing the compiler :-) > > New patch is attached. > > -Stepan. > > > Borja Ferrer wrote: > > Hello Stepan, > The patch looks good, but I have some questions/comments: > > 1) You implemented the "aN" constraint by also allowing b,c,d > constraints. I'm not sure if gcc implements this, my guess is > that only > "a" is needed. Please check to see what gcc does here. > 2) Make getAlternativeRegName return a char instead of a string > since we > only need to return one letter. > 3) Related to the changes in AVRISelLowering.cpp, do we need to care > about more register constraints apart of the ones you already > covered? > 4) Now that wider types have been covered, please check if the > assert I > commented out in AVRISelLowering.cpp in the inline asm code can be > removed or what. > > > > 2013/7/24 Stepan Dyatkovskiy <stp...@na... > <mailto:stp...@na...> <mailto:stp...@na... > <mailto:stp...@na...>>> > > > Hello Borja, > Here is the new patch for multibyte reference. Please look > at new > tests to see what was implemented exactly. > To fix issue I described in previous letter I've added new reg > classes that contains pairs of 8 bit registers: > If we pass i32 parameter that should be split onto four 8 > bit regs, > we set i16 register class first, then it would be replaced > with 8 > bit registers if needed. Currently I see it is the only > solution > that doesn't touch vmcore. > > -Stepan. > > Stepan Dyatkovskiy wrote: > > Hello Borja, > Great. I have found out next inline-asm issue. > When you pass i32 bit type, it could be split onto two > registers > only, > no matter which register class you set for it. This > behaviour is > implemented in SelectionDAGBuilder::____visitInlineAsm. > I think I'll > > implement simplest version of ExpandInlineAsm today, > that will fix > operand types properly. > > -Stepan > > Borja Ferrer wrote: > > I've been adding fixes to pass a ton of regression > in the > Generic folder. > Currently there are two tests that fail with a > "cannot select > build_pair" related to adding 16bit reg classes in the > inline asm code. > The rest of failing tests are related with not > being able to > run llc > with -O0. There's a serious codegen bug that i spotted > yesterday while > doing the fixes that I need to work on. > > > 2013/7/22 Borja Ferrer <bor...@gm... > <mailto:bor...@gm...> > <mailto:bor...@gm... > <mailto:bor...@gm...>> > <mailto:bor...@gm... > <mailto:bor...@gm...> <mailto:bor...@gm... > <mailto:bor...@gm...>>__>__> > > Hello Stepan, > > 3) Yes, it's the second case. It's explained in > http://www.nongnu.org/avr-____libc/user-manual/inline_asm.____html > <http://www.nongnu.org/avr-__libc/user-manual/inline_asm.__html> > > > <http://www.nongnu.org/avr-__libc/user-manual/inline_asm.__html > <http://www.nongnu.org/avr-libc/user-manual/inline_asm.html>> > but in case there are any doubts basically it > works > the same way as > multibyte constraints except that when you see an > "aN", where N is a > number, you should print the alternative > regname. Of > course this > should only work for X Y and Z, not sure how gcc > complains when you > use another register, or maybe it ignores it and > prints the normal > register name. > > > > > > ------------------------------____----------------------------__--__------------------ > > See everything from the browser to the database with > AppDynamics > Get end-to-end visibility with application monitoring from > AppDynamics > Isolate bottlenecks and diagnose root cause in seconds. > Start your free trial of AppDynamics Pro today! > http://pubads.g.doubleclick.____net/gampad/clk?id=48808831&iu=____/4140/ostg.clktrk > > <http://pubads.g.doubleclick.__net/gampad/clk?id=48808831&iu=__/4140/ostg.clktrk > <http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk>> > ___________________________________________________ > avr-llvm-devel mailing list > avr-llvm-devel@lists.__sourcef__orge.net > <http://sourceforge.net> > <mailto:avr-llvm-devel@lists.__sourceforge.net > <mailto:avr...@li...>> > https://lists.sourceforge.net/____lists/listinfo/avr-llvm-__devel <https://lists.sourceforge.net/__lists/listinfo/avr-llvm-devel> > > <https://lists.sourceforge.__net/lists/listinfo/avr-llvm-__devel > <https://lists.sourceforge.net/lists/listinfo/avr-llvm-devel>> > > > > > |
