[VPlan] Use correct constructor when cloning VPWidenIntrinsicRecipe without underlying CallInst

[lukel97]

I noticed this when working on a patch downstream, and I don't think this is an issue upstream yet.

But if a VPWidenIntrinsicRecipe is created without an underlying CallInst, e.g. in createEVLRecipe, it will crash if you try to clone it because it assumes the CallInst always exists.

This fixes it by using the CallInst-less constructor in this case.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Luke Lau (lukel97)

Changes

I noticed this when working on a patch downstream, and I don't think this is an issue upstream yet.

But if a VPWidenIntrinsicRecipe is created without an underlying CallInst, e.g. in createEVLRecipe, it will crash if you try to clone it because it assumes the CallInst always exists.

This fixes it by using the CallInst-less constructor in this case.

---

Full diff: https://github.com/llvm/llvm-project/pull/137493.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Vectorize/VPlan.h (+7-3)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index bd6e15d3fb7a5..925e0b6c68d45 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1347,9 +1347,13 @@ class VPWidenIntrinsicRecipe : public VPRecipeWithIRFlags, public VPIRMetadata {
   ~VPWidenIntrinsicRecipe() override = default;
 
   VPWidenIntrinsicRecipe *clone() override {
-    return new VPWidenIntrinsicRecipe(*cast<CallInst>(getUnderlyingValue()),
-                                      VectorIntrinsicID, {op_begin(), op_end()},
-                                      ResultTy, getDebugLoc());
+    if (auto *CI = getUnderlyingValue())
+      return new VPWidenIntrinsicRecipe(*cast<CallInst>(CI), VectorIntrinsicID,
+                                        {op_begin(), op_end()}, ResultTy,
+                                        getDebugLoc());
+    else
+      return new VPWidenIntrinsicRecipe(
+          VectorIntrinsicID, {op_begin(), op_end()}, ResultTy, getDebugLoc());
   }
 
   VP_CLASSOF_IMPL(VPDef::VPWidenIntrinsicSC)

[fhahn]

We generally prefer leaving clone() implementations unimplemented for cases which are never cloned (such as used in EVL only), but in this cases there may be other places that may want to create VPWidenIntrinsicRecipes w/o underlying instruction

LGTM