[llvm] 7de383c - [VP] Fix VPintrinsic::getStaticVectorLength for vp.merge|select

[Simon Moll via llvm-commits]

Author: Simon Moll
Date: 2022-03-22T11:41:23+01:00
New Revision: 7de383c892135ac7ecb67460c677aed72efdb76a

URL: https://github.com/llvm/llvm-project/commit/7de383c892135ac7ecb67460c677aed72efdb76a
DIFF: https://github.com/llvm/llvm-project/commit/7de383c892135ac7ecb67460c677aed72efdb76a.diff

LOG: [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

Added: 
    

Modified: 
    llvm/include/llvm/IR/VPIntrinsics.def
    llvm/lib/IR/IntrinsicInst.cpp

Removed: 
    


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diff  --git a/llvm/include/llvm/IR/VPIntrinsics.def b/llvm/include/llvm/IR/VPIntrinsics.def
index 093232b7837b9..056601a91a6a1 100644
--- a/llvm/include/llvm/IR/VPIntrinsics.def
+++ b/llvm/include/llvm/IR/VPIntrinsics.def
@@ -397,6 +397,11 @@ HELPER_REGISTER_REDUCTION_SEQ_VP(vp_reduce_fmul, VP_REDUCE_FMUL,
 
 ///// Shuffles {
 
+// The mask 'cond' operand of llvm.vp.select and llvm.vp.merge are not reported
+// as masks with the BEGIN_REGISTER_VP_* macros.  This is because, unlike other
+// VP intrinsics, these two have a defined result on lanes where the mask is
+// false.
+//
 // llvm.vp.select(cond,on_true,on_false,vlen)
 BEGIN_REGISTER_VP(vp_select, None, 3, VP_SELECT, -1)
 VP_PROPERTY_FUNCTIONAL_OPC(Select)

diff  --git a/llvm/lib/IR/IntrinsicInst.cpp b/llvm/lib/IR/IntrinsicInst.cpp
index 4850e301d943f..ad729b09db6ca 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());
 }