Index: llvm/test/Analysis/ScalarEvolution/nuw-add-nested-loops.ll
===================================================================
--- /dev/null
+++ llvm/test/Analysis/ScalarEvolution/nuw-add-nested-loops.ll
@@ -0,0 +1,90 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --force-update
+; RUN: opt < %s -indvars -S | FileCheck %s
+; RUN: opt -S -disable-output "-passes=print<scalar-evolution>" < %s 2>&1 | FileCheck %s --check-prefix=CHECK-ANALYSIS
+
+; At the time test is written it shows that SCEV incorrectly computes flags
+; for expression corresponding to outer_header loop and indvars does an
+; incorrect transformation.
+
+; CHECK-ANALYSIS:  %r.ivi.next = add nuw nsw i32 %r.ivi, 1
+; CHECK-ANALYSIS-NEXT:  -->  {{{{}}-399,+,1}<nuw><nsw><%outer_header>,+,1}<nuw><nsw><%right_header>
+; CHECK-ANALYSIS:  %l.ivi.next = add nsw i32 %l.ivi, 1
+; CHECK-ANALYSIS-NEXT:  -->  {{{{}}-399,+,1}<nuw><nsw><%outer_header>,+,1}<nsw><%left_header>
+define void @test(i1 %c) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[OUTER_HEADER:%.*]]
+; CHECK:       outer_header:
+; CHECK-NEXT:    [[IVO:%.*]] = phi i32 [ -400, [[ENTRY:%.*]] ], [ [[IVO_NEXT:%.*]], [[OUTER_BACKEDGE:%.*]] ]
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[LEFT_HEADER_PREHEADER:%.*]], label [[RIGHT_HEADER_PREHEADER:%.*]]
+; CHECK:       right_header.preheader:
+; CHECK-NEXT:    br label [[RIGHT_HEADER:%.*]]
+; CHECK:       left_header.preheader:
+; CHECK-NEXT:    br label [[LEFT_HEADER:%.*]]
+; CHECK:       right_header:
+; CHECK-NEXT:    [[R_IVI:%.*]] = phi i32 [ [[R_IVI_NEXT:%.*]], [[RIGHT_HEADER]] ], [ [[IVO]], [[RIGHT_HEADER_PREHEADER]] ]
+; CHECK-NEXT:    [[R_IVI_NEXT]] = add nuw nsw i32 [[R_IVI]], 1
+; CHECK-NEXT:    [[R_IVI_NEXT_SDIV:%.*]] = sdiv i32 -1, [[R_IVI_NEXT]]
+; CHECK-NEXT:    [[R_IVI_NEXT_ZEXT:%.*]] = zext i32 [[R_IVI_NEXT_SDIV]] to i64
+; CHECK-NEXT:    call void @bar(i64 [[R_IVI_NEXT_ZEXT]])
+; CHECK-NEXT:    br i1 false, label [[OUTER_BACKEDGE_LOOPEXIT1:%.*]], label [[RIGHT_HEADER]]
+; CHECK:       left_header:
+; CHECK-NEXT:    br i1 false, label [[LEFT_BACKEDGE:%.*]], label [[OUTER_BACKEDGE_LOOPEXIT:%.*]]
+; CHECK:       left_backedge:
+; CHECK-NEXT:    br i1 false, label [[LEFT_EXIT:%.*]], label [[LEFT_HEADER]]
+; CHECK:       left_exit:
+; CHECK-NEXT:    call void @foo()
+; CHECK-NEXT:    br label [[OUTER_BACKEDGE]]
+; CHECK:       outer_backedge.loopexit:
+; CHECK-NEXT:    br label [[OUTER_BACKEDGE]]
+; CHECK:       outer_backedge.loopexit1:
+; CHECK-NEXT:    br label [[OUTER_BACKEDGE]]
+; CHECK:       outer_backedge:
+; CHECK-NEXT:    [[IVO_NEXT]] = add nuw nsw i32 [[IVO]], 1
+; CHECK-NEXT:    [[C_2:%.*]] = icmp sgt i32 [[IVO]], -2
+; CHECK-NEXT:    br i1 [[C_2]], label [[EXIT:%.*]], label [[OUTER_HEADER]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %outer_header
+
+outer_header:
+  %ivo = phi i32 [-400, %entry], [%ivo.next, %outer_backedge]
+  br i1 %c, label %left_header, label %right_header
+
+right_header:
+  %r.ivi = phi i32 [%ivo, %outer_header], [%r.ivi.next, %right_header]
+  %r.ivi.next = add nsw nuw i32 %r.ivi, 1
+; This instruction is required for SCEV to beleive that previous instruction is really nuw.
+  %r.ivi.next.sdiv = sdiv i32 -1, %r.ivi.next
+  %r.ivi.next.zext = zext i32 %r.ivi.next.sdiv to i64
+  call void @bar(i64 %r.ivi.next.zext)
+  %r.c = icmp sgt i32 %r.ivi.next, 1
+  br i1 %r.c, label %outer_backedge, label %right_header
+
+left_header:
+  %l.ivi = phi i32 [%ivo, %outer_header], [%l.ivi.next, %left_backedge]
+  %l.ivi.next = add nsw i32 %l.ivi, 1
+  %l.c = icmp ult i32 %l.ivi.next, 400
+  br i1 %l.c, label %left_backedge, label %outer_backedge
+
+left_backedge:
+  %l.c.2 = icmp sgt i32 %l.ivi, 1
+  br i1 %l.c.2, label %left_exit, label %left_header
+
+left_exit:
+  call void @foo()
+  br label %outer_backedge
+
+outer_backedge:
+  %ivo.next = add nuw nsw i32 %ivo, 1
+  %c.2 = icmp sgt i32 %ivo, -2
+  br i1 %c.2, label %exit, label %outer_header
+
+exit:
+  ret void
+}
+
+declare void @foo() willreturn nounwind
+declare void @bar(i64) willreturn nounwind
Index: llvm/test/Analysis/ScalarEvolution/nuw-add-sibling-loops.ll
===================================================================
--- /dev/null
+++ llvm/test/Analysis/ScalarEvolution/nuw-add-sibling-loops.ll
@@ -0,0 +1,52 @@
+; RUN: opt -S -disable-output "-passes=print<scalar-evolution>" < %s 2>&1 | FileCheck %s --check-prefix=CHECK-ANALYSIS
+
+; At the time test is written it shows that SCEV incorrectly computes flags
+; for expression corresponding to outer_header loop.
+
+; CHECK-ANALYSIS:  %r.ivi.next = add nuw nsw i32 %r.ivi, 1
+; CHECK-ANALYSIS-NEXT:  {{{{}}-399,+,1}<nuw><nsw><%outer_header>,+,1}<nuw><nsw><%right_header>
+; CHECK-ANALYSIS:  %l.ivi.next = add nsw i32 %l.ivi, 1
+; CHECK-ANALYSIS-NEXT:  {{{{}}-399,+,1}<nuw><nsw><%outer_header>,+,1}<nw><%left_header>
+define void @test(i1 %c) {
+entry:
+  br label %outer_header
+
+outer_header:
+  %ivo = phi i32 [-400, %entry], [%ivo.next, %outer_header]
+  %ivo.next = add nuw nsw i32 %ivo, 1
+  %c.2 = icmp sgt i32 %ivo, -2
+  br i1 %c.2, label %outer_exit, label %outer_header
+
+outer_exit:
+  br i1 %c, label %left_header, label %right_header
+
+right_header:
+  %r.ivi = phi i32 [%ivo, %outer_exit], [%r.ivi.next, %right_header]
+  %r.ivi.next = add nsw nuw i32 %r.ivi, 1
+; This instruction is required for SCEV to beleive that previous instruction is really nuw.
+  %r.ivi.next.sdiv = sdiv i32 -1, %r.ivi.next
+  %r.ivi.next.zext = zext i32 %r.ivi.next.sdiv to i64
+  call void @bar(i64 %r.ivi.next.zext)
+  %r.c = icmp sgt i32 %r.ivi.next, 1
+  br i1 %r.c, label %exit, label %right_header
+
+left_header:
+  %l.ivi = phi i32 [%ivo, %outer_exit], [%l.ivi.next, %left_backedge], [%l.ivi.next, %left_exit]
+  %l.ivi.next = add nsw i32 %l.ivi, 1
+  %l.c = icmp ult i32 %l.ivi, 400
+  br i1 %l.c, label %left_backedge, label %left_exit
+
+left_backedge:
+  %l.c.2 = icmp sgt i32 %l.ivi, 1
+  br i1 %l.c.2, label %exit, label %left_header
+
+left_exit:
+  call void @foo()
+  br label %left_header
+
+exit:
+  ret void
+}
+
+declare void @foo() willreturn nounwind
+declare void @bar(i64) willreturn nounwind