llvm dev - Feb 2016 - replace uses of loadInst with a value

Hi,

I need to replace all uses of load instructions with the value of its
operand. Here is an example:

%16 = load i32, i32* %x

%add = add i32 4, %16

In this case, i would like to have the result as:

%add = add i32 4, %x

and then delete the load instruction. I have tried replaceAllUsesWithValue
but i get a type problem.

"llvm::Value::replaceAllUsesWith(llvm::Value*): Assertion
`New->getType()
== getType() && "replaceAllUses of value with new value of
different
type!"' failed."

Best,
Mohammad
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On Fri, Feb 05, 2016 at 11:06:50AM +0100, Mohammad Norouzi via llvm-dev
wrote:
> Hi,
> 
> I need to replace all uses of load instructions with the value of its
> operand. Here is an example:
> 
> %16 = load i32, i32* %x
> 
> %add = add i32 4, %16
> 
> In this case, i would like to have the result as:
> 
> %add = add i32 4, %x
> 
> and then delete the load instruction. I have tried replaceAllUsesWithValue
> but i get a type problem.
> 
> "llvm::Value::replaceAllUsesWith(llvm::Value*): Assertion
`New->getType()
> == getType() && "replaceAllUses of value with new value of
different
> type!"' failed."
Hi Mohammad,

i32* %x and i32 4 don't have the same type, and that triggers the
assert.

If you want to use x as an integer, you should bitcast it, then trunc
or zext it depending on the pointer bitwidth...

hope it helps

So, you are replacing

     add = *x + 4

with

     add = x + 4

(where x is still an `int *x`)

Is that really what you want?

On 5 February 2016 at 10:06, Mohammad Norouzi via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi,
>
> I need to replace all uses of load instructions with the value of its
> operand. Here is an example:
>
> %16 = load i32, i32* %x
>
> %add = add i32 4, %16
>
> In this case, i would like to have the result as:
>
> %add = add i32 4, %x
>
> and then delete the load instruction. I have tried replaceAllUsesWithValue
> but i get a type problem.
>
> "llvm::Value::replaceAllUsesWith(llvm::Value*): Assertion
`New->getType()
> == getType() && "replaceAllUses of value with new value of
different
> type!"' failed."
>
> Best,
> Mohammad
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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