[PATCH] D97859: [LegalizeDAG] Implement promotion rules for SELECT_CC

[LemonBoy via Phabricator via llvm-commits]

LemonBoy added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:4727
+    if (NVT.isInteger()) {
+      ExtOp = isSignedIntSetCC(CCCode) ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
+    }
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craig.topper wrote:
> If NVT is Integer, but operand 0 and 1 are floating point, I'm not sure we should be calling isSignedIntSetCC. The floating point and integer condition codes are shared. So SETGT, SETLT, SETLE, SETGE are also valid for floating point, but they wouldn't mean anything for determining if you should SIGN_EXTEND or ZERO_EXTEND the true/false values of the SELECT_CC.
> 
> But I guess since this hasn't worked properly before now maybe this doesn't happen and it doesn't matter.
I see, this is trickier than anticipated. I'll simply assert that both types are equal and carry on, this promotion rule is rarely used and the only instances I could produce fall into this category.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97859/new/

https://reviews.llvm.org/D97859