[llvm] [VPlan] Handle single-scalar conds in VPWidenSelectRecipe. (PR #165506)

[Florian Hahn via llvm-commits]

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@@ -1757,16 +1757,8 @@ struct LLVM_ABI_FOR_TEST VPWidenSelectRecipe : public VPRecipeWithIRFlags,
     return getOperand(0);
   }
 
-  bool isInvariantCond() const {
-    return getCond()->isDefinedOutsideLoopRegions();
-  }
-
   /// Returns true if the recipe only uses the first lane of operand \p Op.
-  bool onlyFirstLaneUsed(const VPValue *Op) const override {
-    assert(is_contained(operands(), Op) &&
-           "Op must be an operand of the recipe");
-    return Op == getCond() && isInvariantCond();
-  }
+  bool onlyFirstLaneUsed(const VPValue *Op) const override;
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fhahn wrote:

As in pushing the single-scalar check upwards? Currently this is mostly used to determine if we need broadcasts/extracts

https://github.com/llvm/llvm-project/pull/165506