Hi Nick,
Thanks for looking into it.
I have tried that as well but it didn't worked.
"AddExpr->getOperand(0))" node is:
" (4 * (sext i32 {2,+,2}<%for.body4> to i64))<nsw>"
When I cast this to "SCEVAddRecExpr" it returns NULL.
Regards,
Ashutosh
-----Original Message-----
From: Nick Lewycky [mailto:nicholas at mxc.ca]
Sent: Thursday, March 19, 2015 12:19 PM
To: Nema, Ashutosh
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] Cast to SCEVAddRecExpr
Nema, Ashutosh wrote:> Hi,
> I'm trying to cast one of the SCEV node to "SCEVAddRecExpr".
> Every time cast return NULL, and I'm unable to do this.
> SCEV Node:
> ((4 * (sext i32 {2,+,2}<%for.body4> to i64))<nsw> +
%var)<nsw>
> Casting:
> const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(SCEVNode);
> 'var' is of type float pointer (float*).
> Without 'sext' it works, but I'm wondering why it not working
in above case.
> I'm not sure, is such casting allowed ?
It looks like your node is a SCEVAddExpr whose LHS is "(4 * (sext i32
{2,+,2}<%for.body4> to i64))<nsw>" and RHS is "%var",
instead of a
SCEVAddRecExpr. Perhaps if the sext weren't there SCEV might simplify
the whole thing to a single SCEVAddRecExpr.
Can you cast your node to a SCEVAddExpr, then
dyn_cast<SCEVAddRecExpr>(AddExpr->getOperand(0))?
Note that SCEV does not handle floats as anything but completely opaque
values.
Nick
Nema, Ashutosh wrote:> Hi Nick, > > Thanks for looking into it. > > I have tried that as well but it didn't worked. > > "AddExpr->getOperand(0))" node is: > " (4 * (sext i32 {2,+,2}<%for.body4> to i64))<nsw>" > > When I cast this to "SCEVAddRecExpr" it returns NULL.Oh. Yeah, that's because it's a multiply with a 4 on the left. On the right is an sext, and if you grab its operand, then *that* is a SCEVAddRecExpr.> > Regards, > Ashutosh > > -----Original Message----- > From: Nick Lewycky [mailto:nicholas at mxc.ca] > Sent: Thursday, March 19, 2015 12:19 PM > To: Nema, Ashutosh > Cc: llvmdev at cs.uiuc.edu > Subject: Re: [LLVMdev] Cast to SCEVAddRecExpr > > Nema, Ashutosh wrote: >> Hi, >> I'm trying to cast one of the SCEV node to "SCEVAddRecExpr". >> Every time cast return NULL, and I'm unable to do this. >> SCEV Node: >> ((4 * (sext i32 {2,+,2}<%for.body4> to i64))<nsw> + %var)<nsw> >> Casting: >> const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(SCEVNode); >> 'var' is of type float pointer (float*). >> Without 'sext' it works, but I'm wondering why it not working in above case. >> I'm not sure, is such casting allowed ? > > It looks like your node is a SCEVAddExpr whose LHS is "(4 * (sext i32 > {2,+,2}<%for.body4> to i64))<nsw>" and RHS is "%var", instead of a > SCEVAddRecExpr. Perhaps if the sext weren't there SCEV might simplify > the whole thing to a single SCEVAddRecExpr. > > Can you cast your node to a SCEVAddExpr, then > dyn_cast<SCEVAddRecExpr>(AddExpr->getOperand(0))? > > Note that SCEV does not handle floats as anything but completely opaque > values. > > Nick >
Yes, I can get "SCEVAddRecExpr" from operands of "(sext i32
{2,+,2}<%for.body4> to i64)".
So whenever SCEV cast to "SCEVAddRecExpr" fails, we have drill down
for such patterns ?
Is that the right way ?
Regards,
Ashutosh
-----Original Message-----
From: Nick Lewycky [mailto:nicholas at mxc.ca]
Sent: Thursday, March 19, 2015 1:02 PM
To: Nema, Ashutosh
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] Cast to SCEVAddRecExpr
Nema, Ashutosh wrote:> Hi Nick,
>
> Thanks for looking into it.
>
> I have tried that as well but it didn't worked.
>
> "AddExpr->getOperand(0))" node is:
> " (4 * (sext i32 {2,+,2}<%for.body4> to i64))<nsw>"
>
> When I cast this to "SCEVAddRecExpr" it returns NULL.
Oh. Yeah, that's because it's a multiply with a 4 on the left. On the
right is an sext, and if you grab its operand, then *that* is a
SCEVAddRecExpr.
>
> Regards,
> Ashutosh
>
> -----Original Message-----
> From: Nick Lewycky [mailto:nicholas at mxc.ca]
> Sent: Thursday, March 19, 2015 12:19 PM
> To: Nema, Ashutosh
> Cc: llvmdev at cs.uiuc.edu
> Subject: Re: [LLVMdev] Cast to SCEVAddRecExpr
>
> Nema, Ashutosh wrote:
>> Hi,
>> I'm trying to cast one of the SCEV node to
"SCEVAddRecExpr".
>> Every time cast return NULL, and I'm unable to do this.
>> SCEV Node:
>> ((4 * (sext i32 {2,+,2}<%for.body4> to i64))<nsw> +
%var)<nsw>
>> Casting:
>> const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(SCEVNode);
>> 'var' is of type float pointer (float*).
>> Without 'sext' it works, but I'm wondering why it not
working in above case.
>> I'm not sure, is such casting allowed ?
>
> It looks like your node is a SCEVAddExpr whose LHS is "(4 * (sext i32
> {2,+,2}<%for.body4> to i64))<nsw>" and RHS is
"%var", instead of a
> SCEVAddRecExpr. Perhaps if the sext weren't there SCEV might simplify
> the whole thing to a single SCEVAddRecExpr.
>
> Can you cast your node to a SCEVAddExpr, then
> dyn_cast<SCEVAddRecExpr>(AddExpr->getOperand(0))?
>
> Note that SCEV does not handle floats as anything but completely opaque
> values.
>
> Nick
>