[llvm] [VPlan] Remove VPBlendRecipe and replace with select VPInstructions (PR #150369)

[Ramkumar Ramachandra via llvm-commits]

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@@ -8656,9 +8658,11 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
       // latter are added above for masking.
       // FIXME: Migrate code relying on the underlying instruction from VPlan0
       // to construct recipes below to not use the underlying instruction.
-      if (isa<VPCanonicalIVPHIRecipe, VPWidenCanonicalIVRecipe, VPBlendRecipe>(
-              &R) ||
-          (isa<VPInstruction>(&R) && !UnderlyingValue))
+      if (isa<VPCanonicalIVPHIRecipe, VPWidenCanonicalIVRecipe>(&R) ||
+          (isa<VPInstruction>(&R) && !UnderlyingValue) ||
+          (match(&R, m_VPInstruction<Instruction::Select>(
+                         m_VPValue(), m_VPValue(), m_VPValue())) &&
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artagnon wrote:

Would be good to introduce an empty variant of the select matcher?

https://github.com/llvm/llvm-project/pull/150369