[PATCH] D91716: AMDGPU/GlobalISel: Calculate isKnownNeverNaN for fminnum and fmaxnum
Matt Arsenault via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 18 08:37:26 PST 2020
arsenm added inline comments.
================
Comment at: llvm/lib/CodeGen/GlobalISel/Utils.cpp:498-499
+ case TargetOpcode::G_FMAXNUM: {
+ const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
+ return TLI->isKnownNeverNaNForMI(Val, MRI, SNaN);
+ }
----------------
Petar.Avramovic wrote:
> Can this then be `return true`?
No, it depends on the inputs. You can refer to the existing SelectionDAG::isKnownNeverNaN:
```
// Only one needs to be known not-nan, since it will be returned if the
// other ends up being one.
return isKnownNeverNaN(Op.getOperand(0), SNaN, Depth + 1) ||
isKnownNeverNaN(Op.getOperand(1), SNaN, Depth + 1);
```
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D91716/new/
https://reviews.llvm.org/D91716
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