search for: __aeabi_idiv0

Hi, There are several places in compiler-rt which refer to __aeabi_idiv0. For example, in lib/builtins/arm/udivsi3.S: #ifdef __ARM_EABI__ b __aeabi_idiv0 #else JMP(lr) #endif At the same time there is no definition of it. It looks as if it was done intentionally so that third-party could provide custom handler for division by zero. IMHO It's not very con...

Hello, I think the current implementation for the call "bl __aeabi_idiv0" in builtins\arm\udivsi3.S is broken. At least for the case that __aeabi_idiv0 returns. (the provided implementation does) Since LR is not preserved, the following JMP(lr) results in an endless loop. Or is this an intentional change of the behavior? The file contains another implementatio...

Yes, it's a bug. Please review https://reviews.llvm.org/D31716 On 4/5/2017 3:50 AM, Renato Golin wrote: > On 21 March 2017 at 18:32, Peter Jakubek via llvm-dev > <llvm-dev at lists.llvm.org> wrote: >> I think the current implementation for the call "bl __aeabi_idiv0" in >> builtins\arm\udivsi3.S is broken. >> At least for the case that __aeabi_idiv0 returns. (the provided >> implementation does) >> >> Since LR is not preserved, the following JMP(lr) results in an endless loop. >> >> Or is this an intentional chang...

> Looks as though whomever implemented the call to __aeabi_idiv0 wanted > to be conservative for non EABI targets. How could it prevent him from providing default implementation of __aeabi_idiv0() for EABI targets? > AFAIK, gnueabi targets recognize all EABI functions, so that should > work well. Not sure I understand you, nothing in compiler-rt defi...

...ument. > Fair enough. However, the point is that emulating GCC's behavior of the exception is what I was referring to. > Today we return either zero (in divmod/div/mod) or the argument (when > calling div0 directly), and that's just wrong. Quoting the RTABI: 1. int __aeabi_idiv0(int return_value); long long __aeabi_ldiv0(long long return_value); The *div0 functions: 􏰁 Return the value passed to them as a parameter. Is my copy out of date? > > Why 0 and not infinity? Or some other value? > > Because 0 is what it was before. > > cheers,...

...September 2014 02:18, Saleem Abdulrasool <compnerd at compnerd.org> > wrote: > > The current implementations actually return 0. Can you point out where > that > > doesn't hold please? > > With the current implementation... > > int foo(int a) { > return __aeabi_idiv0(a); > } > > returns 'a', while: > > int bar(int a) { > return __aeabi_idiv(a, 0); > } > > returns zero. > > > > Quoting the RTABI: > > > > int __aeabi_idiv0(int return_value); > > long long __aeabi_ldiv0(long long return_value...

On Fri, Sep 5, 2014 at 11:32 AM, Jonathan Roelofs <jonathan at codesourcery.com > wrote: > Sergey, > > Not that it'll save you much hassle, but here's an implementation of > __aeabi_idiv0 and __aeabi_ldiv0 that I've been sitting on for a while. > > I vaguely remember compnerd suggesting that I don't commit them to > compiler_rt, but I don't remember why. > I did dig into this further and it seems that they are, in fact, considered part of the RT-ABI :-(. Iv...

...to Golin wrote: > I'm in favour for adding them ASAP, but we might need an ifdef to avoid > creating unnecessary (or conflicting) symbols for non-EABI targets. Sure, it makes sense. > A proper solution would be to have: > > LOCAL_LABEL(divby0): > #ifdef __ARM_EABI__ > b __aeabi_idiv0 > #else > mov r0, #0 > JMP(lr) > #endif > > And make both __aeabi_{i,l}div0 return 0. > > I'm hoping both parts of the ifdef to generate *identical* code, but > with the benefit that we can change the behaviour of div0 by > overriding the function's impleme...

On Sat, Sep 6, 2014 at 3:40 PM, Renato Golin <renato.golin at linaro.org> wrote: > On 6 September 2014 22:46, Saleem Abdulrasool <compnerd at compnerd.org> > wrote: > > I did dig into this further and it seems that they are, in fact, > considered > > part of the RT-ABI :-(. Ive committed a simple conforming > implementation in > > SVN r217322. > >