llvm dev - Nov 2016 - llvm optimizer turning musttail into tail

I've got some calls like:

musttail call void bitcast (i32 (i32, i8*, %Type*)* @MyMethod to void 
(i32, i8*)*)(i32 %0, i8* %1)
ret void

Into something like:
%8 = tail call i32 @MyMethod(i32 %0, i8* %1, %Type* null)
ret void

I realize I'm losing a parameter there, but this is an interface jump 
trick I use and relies on the end code being a 'jmp' (x86). I realize i 
can probably use noopt & noinline to do this trick, but I do want llvm 
to optimize and inline calls if it can prove it always calls a given 
method. Any way i can do this?

-- 
Carlo Kok
RemObjects Software

On 2016-11-24 14:39, Carlo Kok via llvm-dev wrote:
>
> I've got some calls like:
>
> musttail call void bitcast (i32 (i32, i8*, %Type*)* @MyMethod to void
> (i32, i8*)*)(i32 %0, i8* %1)
> ret void
>
This should have said: that llvm optimizes into something
like:
> %8 = tail call i32 @MyMethod(i32 %0, i8* %1, %Type* null)
> ret void
>
> I realize I'm losing a parameter there, but this is an interface jump
> trick I use and relies on the end code being a 'jmp' (x86). I can
probably
 > use noopt & noinline to do this trick, but I do want
llvm
> to optimize and inline calls if it can prove it always calls a given
> method. Any way i can do this?
>
-- 
Carlo Kok
RemObjects Software

This sounds buggy to me. What pass is doing this?

-- Sean Silva

On Thu, Nov 24, 2016 at 5:39 AM, Carlo Kok via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
>
> I've got some calls like:
>
> musttail call void bitcast (i32 (i32, i8*, %Type*)* @MyMethod to void
> (i32, i8*)*)(i32 %0, i8* %1)
> ret void
>
> Into something like:
> %8 = tail call i32 @MyMethod(i32 %0, i8* %1, %Type* null)
> ret void
>
> I realize I'm losing a parameter there, but this is an interface jump
> trick I use and relies on the end code being a 'jmp' (x86). I
realize i can
> probably use noopt & noinline to do this trick, but I do want llvm to
> optimize and inline calls if it can prove it always calls a given method.
> Any way i can do this?
>
> --
> Carlo Kok
> RemObjects Software
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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r287955 seems like it might be related.

-- Sean Silva

On Sat, Nov 26, 2016 at 4:06 PM, Sean Silva <chisophugis at gmail.com>
wrote:
> This sounds buggy to me. What pass is doing this?
>
> -- Sean Silva
>
> On Thu, Nov 24, 2016 at 5:39 AM, Carlo Kok via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>>
>> I've got some calls like:
>>
>> musttail call void bitcast (i32 (i32, i8*, %Type*)* @MyMethod to void
>> (i32, i8*)*)(i32 %0, i8* %1)
>> ret void
>>
>> Into something like:
>> %8 = tail call i32 @MyMethod(i32 %0, i8* %1, %Type* null)
>> ret void
>>
>> I realize I'm losing a parameter there, but this is an interface
jump
>> trick I use and relies on the end code being a 'jmp' (x86). I
realize i can
>> probably use noopt & noinline to do this trick, but I do want llvm
to
>> optimize and inline calls if it can prove it always calls a given
method.
>> Any way i can do this?
>>
>> --
>> Carlo Kok
>> RemObjects Software
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
>
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