search for: fistp64m

...turns into a call after arranging for the argument to be in ST0. You should emit: %ST0 = COPY %vreg13; RFP80:%vreg13 %EAX, %EDX = FTOL2 %ST0<kill> %vreg16 = COPY %EAX<kill> %vreg17 = COPY %EDX<kill> Then teach X86FloatingPoint that FTOL2 pops its argument, like FISTP64m. 2. Use inline asm. Which is pretty gross. You would need to construct a SelectionDAG node identical to the one produced by real inline asm. There should be some help in include/llvm/InlineAsm.h I am not sure which is worse, but if there are multiple libcalls like this, you should go with somethi...

...g for the argument to be in ST0. >   You should emit: > >   %ST0 = COPY %vreg13; RFP80:%vreg13 >   %EAX, %EDX = FTOL2 %ST0<kill> >   %vreg16 = COPY %EAX<kill> >   %vreg17 = COPY %EDX<kill> > >   Then teach X86FloatingPoint that FTOL2 pops its argument, like FISTP64m. > > 2. Use inline asm. Which is pretty gross. You would need to construct a SelectionDAG node identical to the one produced by real inline asm. There should be some help in include/llvm/InlineAsm.h > > I am not sure which is worse, but if there are multiple libcalls like this, you shou...

2012/1/19 Jakob Stoklund Olesen <stoklund at 2pi.dk>: > How many of these libcalls do you need to implement? What exactly is the calling convention? Which registers are clobbered etc. There is only one (that I know about so far). The MSVCRT `_ftol2` function implements floating-point-to-unsigned conversion for i386 targets, and LLVM 3.0 calls it with the cdecl calling convention for

On Jan 18, 2012, at 8:56 PM, Joe Groff wrote: > 2012/1/18 Jakob Stoklund Olesen <stoklund at 2pi.dk>: >> This should work: >> %1 = call i64 asm "call __ftol2", "=A,{st},~{dirflag},~{fpsr},~{flags},~{st}" (double %x) nounwind > > Forgive me for being slow, but what would be the best way to implement > the equivalent of that inline asm as a custom