[llvm] [LV] Support generating masks for switch terminators. (PR #99808)

[Florian Hahn via llvm-commits]

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@@ -243,16 +440,36 @@ define void @switch_all_to_default(ptr %start) {
 ; IC1-NEXT:    [[GEP:%.*]] = getelementptr inbounds i64, ptr [[START]], i64 [[IV]]
 ; IC1-NEXT:    store i64 42, ptr [[GEP]], align 1
 ; IC1-NEXT:    [[CMP:%.*]] = icmp eq i64 [[IV_NEXT]], 100
-; IC1-NEXT:    br i1 [[CMP]], label %[[EXIT:.*]], label %[[LOOP_HEADER]]
+; IC1-NEXT:    br i1 [[CMP]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP5:![0-9]+]]
 ; IC1:       [[EXIT]]:
 ; IC1-NEXT:    ret void
 ;
 ; IC2-LABEL: define void @switch_all_to_default(
 ; IC2-SAME: ptr [[START:%.*]]) {
 ; IC2-NEXT:  [[ENTRY:.*]]:
+; IC2-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; IC2:       [[VECTOR_PH]]:
+; IC2-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IC2:       [[VECTOR_BODY]]:
+; IC2-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IC2-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; IC2-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 2
+; IC2-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i64, ptr [[START]], i64 [[TMP0]]
+; IC2-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i64, ptr [[START]], i64 [[TMP1]]
+; IC2-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i64, ptr [[TMP2]], i32 0
+; IC2-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i64, ptr [[TMP2]], i32 2
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fhahn wrote:

Yes, this is due to the fact that VPVectorPointerRecipe is responsible to generate pointers for all parts, using only the first part of the pointe operand, but needs marking as only-uses-first-part. Will do separately, thanks!

https://github.com/llvm/llvm-project/pull/99808