search for: tailjmps

tailcall optimization stop working in jit (lli) in revision 45527. i guess this is because the jit is tailjmping to the wrong function address. the following change would reenable tailcallopt in jit. But i am pretty sure that this is not the correct fix (since i don't really understand what is going on :). maybe evan can comment on this? regards arnold Index:

...ful folks on #llvm, that calls across more than 31 bits of address space need to be emitted as a "mov $ADDRESS, r10; call *r10" pair instead of the simple "call rip+ADDRESS" used for calls within 31 bits. But why isn't the mov+call pair emitted inline? And why are Darwin and TAILJMPs special? Having this out of line seems to lose up to 2% performance on the Unladen Swallow benchmarks, so, while it's not urgent, it'd be nice to figure out how to avoid the stubs. What kind of patch would be welcome to fix this? Thanks, Jeffrey

...that calls across > more than 31 bits of address space need to be emitted as a "mov > $ADDRESS, r10; call *r10" pair instead of the simple "call > rip+ADDRESS" used for calls within 31 bits. But why isn't the mov+call > pair emitted inline? And why are Darwin and TAILJMPs special? This is needed because of lazy compilation, before the callee is resolved, it is just a JIT stub. It's heap allocated so it may not be in the lower 4G even if the code size model is small. I know this is the case on Darwin x86_64, I am not sure about other targets. I forgot wh...

...s >> more than 31 bits of address space need to be emitted as a "mov >> $ADDRESS, r10; call *r10" pair instead of the simple "call >> rip+ADDRESS" used for calls within 31 bits. But why isn't the mov+call >> pair emitted inline? And why are Darwin and TAILJMPs special? > > This is needed because of lazy compilation, before the callee is resolved, > it is just a JIT stub. Even with lazy compilation, the contents of the stub get emitted (by JITEmitter::getPointerToGlobal) as a direct call to the function, not the compilation callback, because the...

On Oct 20, 2010, at 11:53 AM, Dan Gohman wrote: > > On Oct 19, 2010, at 8:00 PM, Jakob Stoklund Olesen wrote: >> >> >> One problem is that calling conventions are handled while building the selection DAG, and the DAG doesn't really know to represent clobbered registers. >> >> Perhaps X86TargetLowering::LowerCall() could decorate the X86ISD::CALL node

Great! Are there other issues I should be aware of? Félix Le 2010-11-25 à 07:43:23, Anton Korobeynikov a écrit : > Hello Felix > >> I have a project in mind that involves using the JIT for a few targets (x86 >> and x86_64 processors on Mac OS, Linux and Windows). However, there is an >> open bug that says LLVM generates incorrect code for Win64. >> Eli's last

Felix, > Great! Are there other issues I should be aware of? There might be some issues wrt tailcalls, but I'd not expect anything else to be major broken. -- With best regards, Anton Korobeynikov Faculty of Mathematics and Mechanics, Saint Petersburg State University

Hello list, i am currently trying to implement tail call optimization in the X86 backend , so far i have it working for cases (modulo many unknown bugs :) where the tail called function is a destination within the source file and frame pointer elimination is performed. i implemented it as a dagcombiner transformation running in post legalized phase within the

On Oct 19, 2010, at 8:00 PM, Jakob Stoklund Olesen wrote: > > > One problem is that calling conventions are handled while building the selection DAG, and the DAG doesn't really know to represent clobbered registers. > > Perhaps X86TargetLowering::LowerCall() could decorate the X86ISD::CALL node with the calling convention somehow? > > Dan, do you have any thoughts on

Hello, I am trying to insert a .byte/.word in the beginning of a specific LLVM IR instruction when it prints out in assembly (the inserted ‘instruction' only appears in assembly, not in LLVM IR), and I am guessing the best way to do that is to insert it in SelectionDAG as it strips down some LLVM IR instructions when it’s lowered. Can I get some guidance on what function I should use to insert