LAA: add missed swap when inverting src, sink

When inverting source and sink on a negative induction step, the types
of the source and sink should also be swapped. This fixes a bug in the
code that follows, that computes properties based on these types. With
234cc40 ([LAA] Limit no-overlap check to at least one loop-invariant
accesses.), that code is guarded by a loop-invariant condition: however,
the commit did not add any new tests exercising the guarded code, and
hence the bugfix in this patch requires additional tests to exercise
that guarded codepath.

Author: artagnon

llvm/lib/Analysis/LoopAccessAnalysis.cpp

@@ -1921,6 +1921,7 @@ MemoryDepChecker::getDependenceDistanceStrideAndSize(
   if (StrideAPtr && *StrideAPtr < 0) {
     std::swap(Src, Sink);
     std::swap(AInst, BInst);
+    std::swap(ATy, BTy);
     std::swap(StrideAPtr, StrideBPtr);
   }
 

llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll

@@ -237,13 +237,8 @@ exit:
 define void @type_size_equivalence_sink_loopinv_negind(ptr nocapture %vec, i64 %n) {
 ; CHECK-LABEL: 'type_size_equivalence_sink_loopinv_negind'
 ; CHECK-NEXT:    loop:
-; CHECK-NEXT:      Report: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
-; CHECK-NEXT:  Unknown data dependence.
+; CHECK-NEXT:      Memory dependences are safe
 ; CHECK-NEXT:      Dependences:
-; CHECK-NEXT:        Unknown:
-; CHECK-NEXT:            %ld.i64 = load i64, ptr %gep.minus.iv.4, align 8 ->
-; CHECK-NEXT:            store i32 %ld.i64.i32, ptr %gep.minus.n, align 8
-; CHECK-EMPTY:
 ; CHECK-NEXT:      Run-time memory checks:
 ; CHECK-NEXT:      Grouped accesses:
 ; CHECK-EMPTY: