[VP] Fix VPintrinsic::getStaticVectorLength for vp.merge|select

VPIntrinsic::getStaticVectorLength infers the operational vector length
of a VPIntrinsic instance from a type that is used with the intrinsic.
The function used the mask operand before. Yet, vp.merge|select do not
have a mask operand (in the predicating sense that the other VP
intrinsics are using them - it is a selection mask for them). Fallback
to the return type to fix this.

Reviewed By: kaz7

Differential Revision: https://reviews.llvm.org/D121913

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/IR/IntrinsicInst.cpp b/llvm/lib/IR/IntrinsicInst.cpp
index 4850e30..ad729b0 100644
--- a/llvm/lib/IR/IntrinsicInst.cpp
+++ b/llvm/lib/IR/IntrinsicInst.cpp
@@ -299,7 +299,12 @@ ElementCount VPIntrinsic::getStaticVectorLength() const {
   };
 
   Value *VPMask = getMaskParam();
-  assert(VPMask && "No mask param?");
+  if (!VPMask) {
+    assert((getIntrinsicID() == Intrinsic::vp_merge ||
+            getIntrinsicID() == Intrinsic::vp_select) &&
+           "Unexpected VP intrinsic without mask operand");
+    return GetVectorLengthOfType(getType());
+  }
   return GetVectorLengthOfType(VPMask->getType());
 }