[VPlan] Preserve dbg location on canonical IVs in native path.

Pass the debug location of the primary IV to addCanonicalIVRecipes in
the native path, matching the behavior of inner loop vectorization.

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -9760,8 +9760,9 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlan(VFRange &Range) {
   // Tail folding is not supported for outer loops, so the induction increment
   // is guaranteed to not wrap.
   bool HasNUW = true;
-  addCanonicalIVRecipes(*Plan, Legal->getWidestInductionType(), HasNUW,
-                        DebugLoc());
+  addCanonicalIVRecipes(
+      *Plan, Legal->getWidestInductionType(), HasNUW,
+      getDebugLocFromInstOrOperands(Legal->getPrimaryInduction()));
 
   if (!VPlanTransforms::tryToConvertVPInstructionsToVPRecipes(
           Plan,

llvm/test/Transforms/LoopVectorize/dbg-outer-loop-vect.ll

@@ -12,7 +12,7 @@ define void @foo(ptr %h) !dbg !4 {
 ; CHECK:       vector.ph:
 ; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]], !dbg [[DBG21]]
 ; CHECK:       vector.body:
-; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[FOR_COND_CLEANUP32:%.*]] ]
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[FOR_COND_CLEANUP32:%.*]] ], !dbg [[DBG222:![0-9]+]]
 ; CHECK-NEXT:    br label [[FOR_COND5_PREHEADER1:%.*]], !dbg [[DBG21]]
 ; CHECK:       for.cond5.preheader1:
 ; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ zeroinitializer, [[VECTOR_BODY]] ], [ [[TMP4:%.*]], [[FOR_COND5_PREHEADER1]] ], !dbg [[DBG22:![0-9]+]]
@@ -29,9 +29,9 @@ define void @foo(ptr %h) !dbg !4 {
 ; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <4 x i1> [[TMP5]], i32 0, !dbg [[DBG28:![0-9]+]]
 ; CHECK-NEXT:    br i1 [[TMP6]], label [[FOR_COND_CLEANUP32]], label [[FOR_COND5_PREHEADER1]], !dbg [[DBG28]]
 ; CHECK:       vector.latch:
-; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
-; CHECK-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], 20
-; CHECK-NEXT:    br i1 [[TMP9]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP29:![0-9]+]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4, !dbg [[DBG222]]
+; CHECK-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[INDEX_NEXT]], 20, !dbg [[DBG222]]
+; CHECK-NEXT:    br i1 [[TMP9]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !dbg [[DBG222]], !llvm.loop [[LOOP29:![0-9]+]]
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    br i1 false, label [[EXIT:%.*]], label [[SCALAR_PH]], !dbg [[DBG21]]
 ; CHECK:       scalar.ph:
@@ -156,6 +156,7 @@ declare void @llvm.dbg.value(metadata, metadata, metadata)
 ; CHECK: [[META19]] = distinct !DILexicalBlock(scope: [[META15]], file: [[META1]], line: 11, column: 5)
 ; CHECK: [[META20]] = !DILocation(line: 0, scope: [[META12]])
 ; CHECK: [[DBG21]] = !DILocation(line: 10, column: 3, scope: [[META12]])
+; CHECK: [[DBG222]] = !DILocation(line: 10, column: 30, scope: [[META16]])
 ; CHECK: [[DBG22]] = !DILocation(line: 10, column: 5, scope: [[META12]])
 ; CHECK: [[DBG23]] = !DILocation(line: 13, column: 11, scope: [[META24:![0-9]+]])
 ; CHECK: [[META24]] = distinct !DILexicalBlock(scope: [[META18]], file: [[META1]], line: 12, column: 7)
@@ -167,7 +168,6 @@ declare void @llvm.dbg.value(metadata, metadata, metadata)
 ; CHECK: [[META30]] = !DILocation(line: 13, column: 13, scope: [[META12]])
 ; CHECK: [[META31]] = !{!"llvm.loop.isvectorized", i32 1}
 ; CHECK: [[META32]] = !{!"llvm.loop.unroll.runtime.disable"}
-; CHECK: [[DBG33]] = !DILocation(line: 10, column: 30, scope: [[META16]])
 ; CHECK: [[DBG34]] = !DILocation(line: 10, column: 24, scope: [[META16]])
 ; CHECK: [[LOOP35]] = distinct !{[[LOOP35]], [[DBG21]], [[META30]], [[META31]]}
 ; CHECK: [[DBG36]] = !DILocation(line: 14, column: 1, scope: [[DBG4]])