llvm dev - Sep 2013 - [LLVMdev] "Instruction does not dominate all uses"

BB:
  %4= load i32* @"FB"
  %5 = icmp ne i32 %4, 0
  br i1 %5, label %BB1, label %BB2

The error after

$clang -pthread MyNew.ll -o  MyNew

Instruction does not dominate all uses!

Could you help for this ?


-- 
*     Rasha Salah Omar
     Msc Student at E-JUST
     Demonestrator  at Faculty of Computers and Informatics
     Benha University*

*     e-mail: rasha.omar at ejust.edu.eg*
 P* Please consider the environment before printing this email.*
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Hi Rasha,
> Instruction does not dominate all uses!
There should be two instructions printed after that message. The first
defines a value used by the second, but the message means there's some
path through your function that can reach the second inst (the use)
without the value being defined by the first instruction.

At its simplest you probably want to decide what that value should be
if the defining instruction isn't reached (maybe an initial loop
value?), insert a phi node describing this and use that instead of the
instruction that may not be executed.
> Could you help for this ?
Not without more information, I'm afraid. The fragment you posted has no
issues.

Cheers.

Tim.

Hi Tim,

Instruction does not dominate all uses!
%5 = icmp ne i32 %4, 0
 br i1 %5, label %BB1, label %BB2
Broken module found, compilation aborted!





On 8 September 2013 11:58, Tim Northover <t.p.northover at gmail.com>
wrote:
> Hi Rasha,
>
> > Instruction does not dominate all uses!
>
> There should be two instructions printed after that message. The first
> defines a value used by the second, but the message means there's some
> path through your function that can reach the second inst (the use)
> without the value being defined by the first instruction.
>
> At its simplest you probably want to decide what that value should be
> if the defining instruction isn't reached (maybe an initial loop
> value?), insert a phi node describing this and use that instead of the
> instruction that may not be executed.
>
> > Could you help for this ?
>
> Not without more information, I'm afraid. The fragment you posted has
no
> issues.
>
> Cheers.
>
> Tim.
>


-- 
*     Rasha Salah Omar
     Msc Student at E-JUST
     Demonestrator  at Faculty of Computers and Informatics
     Benha University*

*     e-mail: rasha.omar at ejust.edu.eg*
 P* Please consider the environment before printing this email.*
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