Use const, update EVL comment, remove noalias, rename test

Author: lukel97

llvm/lib/Analysis/VectorUtils.cpp

@@ -149,8 +149,7 @@ bool llvm::isVectorIntrinsicWithScalarOpAtArg(Intrinsic::ID ID,
   if (TTI && Intrinsic::isTargetIntrinsic(ID))
     return TTI->isTargetIntrinsicWithScalarOpAtArg(ID, ScalarOpdIdx);
 
-  // Vector predication intrinsics only demand the the first lane the last
-  // operand (the EVL operand).
+  // Vector predication intrinsics have the EVL as the last operand.
   if (VPIntrinsic::getVectorLengthParamPos(ID) == ScalarOpdIdx)
     return true;
 

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -1364,7 +1364,7 @@ StringRef VPWidenIntrinsicRecipe::getIntrinsicName() const {
 
 bool VPWidenIntrinsicRecipe::onlyFirstLaneUsed(const VPValue *Op) const {
   assert(is_contained(operands(), Op) && "Op must be an operand of the recipe");
-  return all_of(enumerate(operands()), [this, &Op](auto &&X) {
+  return all_of(enumerate(operands()), [this, &Op](const auto &X) {
     auto [Idx, V] = X;
     return V != Op || isVectorIntrinsicWithScalarOpAtArg(getVectorIntrinsicID(),
                                                          Idx, nullptr);

llvm/test/Transforms/LoopVectorize/widen-intrinsic.ll

@@ -2,9 +2,9 @@
 ; RUN: opt < %s -passes=loop-vectorize -force-vector-width=4 -S | FileCheck %s
 
 ; Check that we don't unnecessarily broadcast %pow
-define void @powi(ptr noalias %p, i32 %pow) {
-; CHECK-LABEL: define void @powi(
-; CHECK-SAME: ptr noalias [[P:%.*]], i32 [[POW:%.*]]) {
+define void @powi_only_first_lane_used_of_second_arg(ptr %p, i32 %pow) {
+; CHECK-LABEL: define void @powi_only_first_lane_used_of_second_arg(
+; CHECK-SAME: ptr [[P:%.*]], i32 [[POW:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*]]:
 ; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
 ; CHECK:       [[VECTOR_PH]]:
@@ -14,11 +14,11 @@ define void @powi(ptr noalias %p, i32 %pow) {
 ; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr float, ptr [[P]], i32 [[INDEX]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr float, ptr [[TMP0]], i32 0
 ; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x float>, ptr [[TMP1]], align 4
-; CHECK-NEXT:    [[TMP3:%.*]] = call <4 x float> @llvm.powi.v4f32.i32(<4 x float> [[WIDE_LOAD]], i32 [[POW]])
-; CHECK-NEXT:    store <4 x float> [[TMP3]], ptr [[TMP1]], align 4
+; CHECK-NEXT:    [[TMP2:%.*]] = call <4 x float> @llvm.powi.v4f32.i32(<4 x float> [[WIDE_LOAD]], i32 [[POW]])
+; CHECK-NEXT:    store <4 x float> [[TMP2]], ptr [[TMP1]], align 4
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 4
-; CHECK-NEXT:    [[TMP4:%.*]] = icmp eq i32 [[INDEX_NEXT]], 1024
-; CHECK-NEXT:    br i1 [[TMP4]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[INDEX_NEXT]], 1024
+; CHECK-NEXT:    br i1 [[TMP3]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
 ; CHECK-NEXT:    br i1 true, label %[[EXIT:.*]], label %[[SCALAR_PH]]
 ; CHECK:       [[SCALAR_PH]]: