Allow vectorization of intrinsics such as powi,cttz and ctlz in Loop and SLP Vectorizer.

This patch adds support to vectorize intrinsics such as powi, cttz and ctlz in Vectorizer. These intrinsics are different from other
intrinsics as second argument to these function must be same in order to vectorize them and it should be represented as a scalar.
Review: http://reviews.llvm.org/D3851#inline-32769 and http://reviews.llvm.org/D3937#inline-32857

llvm-svn: 209873

1 files changed, 27 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index e13ba956c39..ce0a009e1cb 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -961,9 +961,10 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth) {
         DEBUG(dbgs() << "SLP: Non-vectorizable call.\n");
         return;
       }
-
       Function *Int = CI->getCalledFunction();
-
+      Value *A1I = nullptr;
+      if (hasVectorInstrinsicScalarOpd(ID, 1))
+        A1I = CI->getArgOperand(1);
       for (unsigned i = 1, e = VL.size(); i != e; ++i) {
         CallInst *CI2 = dyn_cast<CallInst>(VL[i]);
         if (!CI2 || CI2->getCalledFunction() != Int ||
@@ -973,6 +974,18 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth) {
                        << "\n");
           return;
         }
+        // ctlz,cttz and powi are special intrinsics whose second argument
+        // should be same in order for them to be vectorized.
+        if (hasVectorInstrinsicScalarOpd(ID, 1)) {
+          Value *A1J = CI2->getArgOperand(1);
+          if (A1I != A1J) {
+            newTreeEntry(VL, false);
+            DEBUG(dbgs() << "SLP: mismatched arguments in call:" << *CI
+                         << " argument "<< A1I<<"!=" << A1J
+                         << "\n");
+            return;
+          }
+        }
       }
 
       newTreeEntry(VL, true);
@@ -1652,9 +1665,21 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
     case Instruction::Call: {
       CallInst *CI = cast<CallInst>(VL0);
       setInsertPointAfterBundle(E->Scalars);
+      Function *FI;
+      Intrinsic::ID IID  = Intrinsic::not_intrinsic;
+      if (CI && (FI = CI->getCalledFunction())) {
+        IID = (Intrinsic::ID) FI->getIntrinsicID();
+      }
       std::vector<Value *> OpVecs;
       for (int j = 0, e = CI->getNumArgOperands(); j < e; ++j) {
         ValueList OpVL;
+        // ctlz,cttz and powi are special intrinsics whose second argument is
+        // a scalar. This argument should not be vectorized.
+        if (hasVectorInstrinsicScalarOpd(IID, 1) && j == 1) {
+          CallInst *CEI = cast<CallInst>(E->Scalars[0]);
+          OpVecs.push_back(CEI->getArgOperand(j));
+          continue;
+        }
         for (int i = 0, e = E->Scalars.size(); i < e; ++i) {
           CallInst *CEI = cast<CallInst>(E->Scalars[i]);
           OpVL.push_back(CEI->getArgOperand(j));