[VPlan] Add ExplicitVectorLength to isSingleScalar

[michaelmaitland]

The docstring of this function:

Returns true if this VPInstruction's operands are single scalars and the
result is also a single scalar.

ExplicitVectorLength fits this description. I don't have a test for it now, but it is needed by #106560.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Michael Maitland (michaelmaitland)

Changes

The docstring of this function:

> Returns true if this VPInstruction's operands are single scalars and the
> result is also a single scalar.

ExplicitVectorLength fits this description. I don't have a test for it now, but it is needed by #106560.

---

Full diff: https://github.com/llvm/llvm-project/pull/106818.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp (+2-1)

diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index f84317ba51257a..5877aae81a7955 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -680,7 +680,8 @@ bool VPInstruction::isVectorToScalar() const {
 }
 
 bool VPInstruction::isSingleScalar() const {
-  return getOpcode() == VPInstruction::ResumePhi;
+  return getOpcode() == VPInstruction::ResumePhi ||
+         getOpcode() == VPInstruction::ExplicitVectorLength;
 }
 
 #if !defined(NDEBUG)

[artagnon]

While I appreciate that this is not going to be easy to test, I believe a test is a hard requirement to support the change.