[llvm] [VPlan] Use VPTypeAnalysis to get the step type of widen pointer induction (PR #147925)

[David Sherwood via llvm-commits]

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@@ -0,0 +1,75 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -lv-strided-pointer-ivs -S < %s | FileCheck %s
+
+define i64 @widen_ptr_indvar(ptr noalias %a, ptr noalias %b ,i64 %stride, i64 %n) {
+; CHECK-LABEL: define i64 @widen_ptr_indvar(
+; CHECK-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], i64 [[STRIDE:%.*]], i64 [[N:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:    [[TMP9:%.*]] = add i64 [[N]], 1
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i64 [[STRIDE]], 3
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP9]], 4
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP9]], 4
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP9]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP2:%.*]] = mul i64 [[N_VEC]], [[TMP1]]
+; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i8, ptr null, i64 [[TMP2]]
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[INDEX]]
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr [[TMP4]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i64>, ptr [[TMP5]], align 8
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <4 x i64> [[WIDE_LOAD]], i32 3
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP9]], [[N_VEC]]
+; CHECK-NEXT:    [[TMP8:%.*]] = sub i64 0, [[TMP1]]
+; CHECK-NEXT:    [[IND_ESCAPE:%.*]] = getelementptr i8, ptr [[TMP3]], i64 [[TMP8]]
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david-arm wrote:

Is it possible to also have a test case where the widened pointer induction is used inside the loop?

https://github.com/llvm/llvm-project/pull/147925