[LV] Add test for diff check creation order.

Add a test where diff checks are generated initial and then re-generated
when re-trying with runtime checks.

At the moment, the order doesn't match the order they are created in, as
the DiffChecks field in LAI isn't cleared as other fields holding
runtime checks.

Author: fhahn

llvm/test/Transforms/LoopVectorize/runtime-checks-difference-simplifications.ll

@@ -222,3 +222,78 @@ loop:
 exit:
   ret void
 }
+
+define void @check_creation_order(ptr %a, ptr %b, i32 %m) {
+; CHECK-LABEL: @check_creation_order(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[B2:%.*]] = ptrtoint ptr [[B:%.*]] to i64
+; CHECK-NEXT:    [[A1:%.*]] = ptrtoint ptr [[A:%.*]] to i64
+; CHECK-NEXT:    [[M_EXT:%.*]] = sext i32 [[M:%.*]] to i64
+; CHECK-NEXT:    [[INVARIANT_GEP:%.*]] = getelementptr double, ptr [[A]], i64 [[M_EXT]]
+; CHECK-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_MEMCHECK:%.*]]
+; CHECK:       vector.memcheck:
+; CHECK-NEXT:    [[TMP0:%.*]] = sub i64 [[A1]], [[B2]]
+; CHECK-NEXT:    [[DIFF_CHECK:%.*]] = icmp ult i64 [[TMP0]], 32
+; CHECK-NEXT:    [[TMP1:%.*]] = mul nsw i64 [[M_EXT]], -8
+; CHECK-NEXT:    [[DIFF_CHECK3:%.*]] = icmp ult i64 [[TMP1]], 32
+; CHECK-NEXT:    [[CONFLICT_RDX:%.*]] = or i1 [[DIFF_CHECK]], [[DIFF_CHECK3]]
+; CHECK-NEXT:    br i1 [[CONFLICT_RDX]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr double, ptr [[INVARIANT_GEP]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr double, ptr [[TMP3]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x double>, ptr [[TMP4]], align 8
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr inbounds double, ptr [[B]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr inbounds double, ptr [[TMP5]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD4:%.*]] = load <4 x double>, ptr [[TMP6]], align 8
+; CHECK-NEXT:    [[TMP7:%.*]] = fadd <4 x double> [[WIDE_LOAD]], [[WIDE_LOAD4]]
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr inbounds double, ptr [[A]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds double, ptr [[TMP8]], i32 0
+; CHECK-NEXT:    store <4 x double> [[TMP7]], ptr [[TMP9]], align 8
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT:    [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], 31996
+; CHECK-NEXT:    br i1 [[TMP10]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    br i1 false, label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 31996, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ], [ 0, [[VECTOR_MEMCHECK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr double, ptr [[INVARIANT_GEP]], i64 [[IV]]
+; CHECK-NEXT:    [[L_0:%.*]] = load double, ptr [[GEP]], align 8
+; CHECK-NEXT:    [[GEP_B:%.*]] = getelementptr inbounds double, ptr [[B]], i64 [[IV]]
+; CHECK-NEXT:    [[L_1:%.*]] = load double, ptr [[GEP_B]], align 8
+; CHECK-NEXT:    [[ADD3:%.*]] = fadd double [[L_0]], [[L_1]]
+; CHECK-NEXT:    [[GEP_A:%.*]] = getelementptr inbounds double, ptr [[A]], i64 [[IV]]
+; CHECK-NEXT:    store double [[ADD3]], ptr [[GEP_A]], align 8
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], 31999
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  %m.ext = sext i32 %m to i64
+  %invariant.gep = getelementptr double, ptr %a, i64 %m.ext
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %gep = getelementptr double, ptr %invariant.gep, i64 %iv
+  %l.0 = load double, ptr %gep, align 8
+  %gep.b = getelementptr inbounds double, ptr %b, i64 %iv
+  %l.1 = load double, ptr %gep.b, align 8
+  %add3 = fadd double %l.0, %l.1
+  %gep.a = getelementptr inbounds double, ptr %a, i64 %iv
+  store double %add3, ptr %gep.a, align 8
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond.not = icmp eq i64 %iv.next, 31999
+  br i1 %exitcond.not, label %exit, label %loop
+
+exit:
+  ret void
+}