[LV] Address review

Author: artagnon

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -7488,6 +7488,8 @@ VPRecipeBuilder::tryToWidenMemory(Instruction *I, ArrayRef<VPValue *> Operands,
     if (Reverse) {
       // When folding the tail, we may compute an address that we don't in the
       // original scalar loop: drop the GEP no-wrap flags in this case.
+      // Otherwise preserve existing flags without no-unsigned-wrap, as we will
+      // emit negative indices.
       GEPNoWrapFlags Flags =
           CM.foldTailByMasking() || !GEP
               ? GEPNoWrapFlags::none()

llvm/test/Transforms/LoopVectorize/reverse-induction-gep-nowrap-flags.ll

@@ -1,5 +1,5 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt < %s -passes=loop-vectorize -force-vector-width=4 -S | FileCheck %s
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 6
+; RUN: opt -passes=loop-vectorize -force-vector-width=4 -S %s | FileCheck %s
 
 define i32 @preserve_inbounds(i64 %start, ptr %ptr) {
 ; CHECK-LABEL: define i32 @preserve_inbounds(
@@ -180,10 +180,3 @@ loop:
 end:
   ret i32 %redux.next
 }
-;.
-; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
-; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
-; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
-; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]], [[META2]]}
-; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
-;.