[LAA] Add additional test

Author: artagnon

llvm/test/Analysis/LoopAccessAnalysis/long-pointer-distance.ll

@@ -1,8 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
 ; RUN: opt -passes='print<access-info>' -disable-output %s 2>&1 | FileCheck %s
 
-define void @test(ptr %this, i128 %loop.limit) {
-; CHECK-LABEL: 'test'
+define void @forward_i128_offset_difference(ptr %this, i128 %loop.limit) {
+; CHECK-LABEL: 'forward_i128_offset_difference'
 ; CHECK-NEXT:    loop:
 ; CHECK-NEXT:      Memory dependences are safe
 ; CHECK-NEXT:      Dependences:
@@ -35,3 +35,39 @@ exit:
   ret void
 }
 
+define void @backward_distance_offset_subtract(ptr %A) {
+; CHECK-LABEL: 'backward_distance_offset_subtract'
+; CHECK-NEXT:    loop:
+; CHECK-NEXT:      Memory dependences are safe
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:        Forward:
+; CHECK-NEXT:            %l = load i32, ptr %gep.off.1, align 4 ->
+; CHECK-NEXT:            store i32 %add, ptr %gep.off.2, align 4
+; CHECK-EMPTY:
+; 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:
+  %A.off.1 = getelementptr inbounds i8, ptr %A, i64 u0x100000018
+  %A.off.2 = getelementptr inbounds i8, ptr %A, i64 u0x100000010
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  %gep.off.1 = getelementptr inbounds i32, ptr %A.off.1, i64 %iv
+  %l = load i32, ptr %gep.off.1, align 4
+  %add = add nsw i32 %l, 5
+  %gep.off.2 = getelementptr inbounds i32, ptr %A.off.2, i64 %iv
+  store i32 %add, ptr %gep.off.2, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond.not = icmp eq i64 %iv.next, 256
+  br i1 %exitcond.not, label %exit, label %loop
+
+exit:
+  ret void
+}