[LAA] Add test for llvm#79137 (NFC)

(cherry picked from commit 0c02b2e)

Author: nikic

llvm/test/Analysis/LoopAccessAnalysis/noalias-scope-decl.ll

@@ -0,0 +1,94 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -passes='print<access-info>' -disable-output 2>&1 < %s | FileCheck %s
+
+; PR79137: If the noalias.scope.decl is located inside the loop, we cannot
+; assume that the accesses don't alias across iterations.
+
+define void @test_scope_in_loop(ptr %arg, i64 %num) {
+; CHECK-LABEL: 'test_scope_in_loop'
+; CHECK-NEXT:    loop:
+; CHECK-NEXT:      Memory dependences are safe
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:      SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Expressions re-written:
+;
+entry:
+  %icmp = icmp ult i64 %num, 2
+  br i1 %icmp, label %exit, label %preheader
+
+preheader:
+  %arg.1 = getelementptr inbounds i8, ptr %arg, i64 1
+  %end = add i64 %num, -2
+  br label %loop
+
+loop:
+  %prev.ptr = phi ptr [ %cur.ptr, %loop ], [ %arg, %preheader ]
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %preheader ]
+  %cur.ptr = getelementptr inbounds i8, ptr %arg.1, i64 %iv
+  call void @llvm.experimental.noalias.scope.decl(metadata !0)
+  call void @llvm.experimental.noalias.scope.decl(metadata !3)
+  %load.prev = load i8, ptr %prev.ptr, align 1, !alias.scope !0, !noalias !3
+  %load.cur = load i8, ptr %cur.ptr, align 1, !alias.scope !3
+  %add = add i8 %load.cur, %load.prev
+  store i8 %add, ptr %cur.ptr, align 1, !alias.scope !3
+  %iv.next = add nuw i64 %iv, 1
+  %cmp = icmp eq i64 %iv, %end
+  br i1 %cmp, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+define void @test_scope_out_of_loop(ptr %arg, i64 %num) {
+; CHECK-LABEL: 'test_scope_out_of_loop'
+; CHECK-NEXT:    loop:
+; CHECK-NEXT:      Memory dependences are safe
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:      SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Expressions re-written:
+;
+entry:
+  %icmp = icmp ult i64 %num, 2
+  br i1 %icmp, label %exit, label %preheader
+
+preheader:
+  call void @llvm.experimental.noalias.scope.decl(metadata !0)
+  call void @llvm.experimental.noalias.scope.decl(metadata !3)
+  %arg.1 = getelementptr inbounds i8, ptr %arg, i64 1
+  %end = add i64 %num, -2
+  br label %loop
+
+loop:
+  %prev.ptr = phi ptr [ %cur.ptr, %loop ], [ %arg, %preheader ]
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %preheader ]
+  %cur.ptr = getelementptr inbounds i8, ptr %arg.1, i64 %iv
+  %load.prev = load i8, ptr %prev.ptr, align 1, !alias.scope !0, !noalias !3
+  %load.cur = load i8, ptr %cur.ptr, align 1, !alias.scope !3
+  %add = add i8 %load.cur, %load.prev
+  store i8 %add, ptr %cur.ptr, align 1, !alias.scope !3
+  %iv.next = add nuw i64 %iv, 1
+  %cmp = icmp eq i64 %iv, %end
+  br i1 %cmp, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+declare void @llvm.experimental.noalias.scope.decl(metadata)
+
+!0 = !{!1}
+!1 = distinct !{!1, !2}
+!2 = distinct !{!2}
+!3 = !{!4}
+!4 = distinct !{!4, !5}
+!5 = distinct !{!5}