[LV] Use ScalarParts for ad-hoc pointer IV scalarization (NFCI)

We can now maintain scalar values in VectorLoopValueMap. Thus, we no longer
have to create temporary vectors with insertelement instructions when handling
pointer induction variables. This case was mistakenly missed from r279649 when
refactoring the other scalarization code.

llvm-svn: 280405

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 15e82dd..9add69d 100644 (file)
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4453,33 +4453,20 @@ void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN, unsigned UF,
     // This is the normalized GEP that starts counting at zero.
     Value *PtrInd = Induction;
     PtrInd = Builder.CreateSExtOrTrunc(PtrInd, II.getStep()->getType());
-    // This is the vector of results. Notice that we don't generate
-    // vector geps because scalar geps result in better code.
-    VectorParts Entry(UF);
-    for (unsigned part = 0; part < UF; ++part) {
-      if (VF == 1) {
-        int EltIndex = part;
-        Constant *Idx = ConstantInt::get(PtrInd->getType(), EltIndex);
-        Value *GlobalIdx = Builder.CreateAdd(PtrInd, Idx);
-        Value *SclrGep = II.transform(Builder, GlobalIdx, PSE.getSE(), DL);
-        SclrGep->setName("next.gep");
-        Entry[part] = SclrGep;
-        continue;
-      }
-
-      Value *VecVal = UndefValue::get(VectorType::get(P->getType(), VF));
-      for (unsigned int i = 0; i < VF; ++i) {
-        int EltIndex = i + part * VF;
-        Constant *Idx = ConstantInt::get(PtrInd->getType(), EltIndex);
+    // These are the scalar results. Notice that we don't generate vector GEPs
+    // because scalar GEPs result in better code.
+    ScalarParts Entry(UF);
+    for (unsigned Part = 0; Part < UF; ++Part) {
+      Entry[Part].resize(VF);
+      for (unsigned Lane = 0; Lane < VF; ++Lane) {
+        Constant *Idx = ConstantInt::get(PtrInd->getType(), Lane + Part * VF);
         Value *GlobalIdx = Builder.CreateAdd(PtrInd, Idx);
         Value *SclrGep = II.transform(Builder, GlobalIdx, PSE.getSE(), DL);
         SclrGep->setName("next.gep");
-        VecVal = Builder.CreateInsertElement(VecVal, SclrGep,
-                                             Builder.getInt32(i), "insert.gep");
+        Entry[Part][Lane] = SclrGep;
       }
-      Entry[part] = VecVal;
     }
-    VectorLoopValueMap.initVector(P, Entry);
+    VectorLoopValueMap.initScalar(P, Entry);
     return;
   }
   case InductionDescriptor::IK_FpInduction: {