diff --git a/llvm/test/Transforms/InstCombine/known-phi-br.ll b/llvm/test/Transforms/InstCombine/known-phi-br.ll
new file mode 100644
index 0000000000000..a3079860b62e3
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/known-phi-br.ll
@@ -0,0 +1,157 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=instcombine < %s | FileCheck %s
+
+;
+; Tests to show cases where computeKnownBits should be able to determine
+; the known bits of a phi edge based off a conditional branch feeding the phi.
+;
+
+; TODO: %x either eq 7 or is set to 7
+define i64 @limit_i64_eq_7(i64 %x) {
+; CHECK-LABEL: @limit_i64_eq_7(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i64 [[X:%.*]], 7
+; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[RES:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ 7, [[BODY]] ]
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp eq i64 %x, 7
+  br i1 %cmp, label %end, label %body
+body:
+  br label %end
+end:
+  %res = phi i64 [ %x, %entry ], [ 7, %body ]
+  ret i64 %res
+}
+
+; TODO: %x either eq 255 or is set to 255
+define i64 @limit_i64_ne_255(i64 %x) {
+; CHECK-LABEL: @limit_i64_ne_255(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP_NOT:%.*]] = icmp eq i64 [[X:%.*]], 255
+; CHECK-NEXT:    br i1 [[CMP_NOT]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[RES:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ 255, [[BODY]] ]
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp ne i64 %x, 255
+  br i1 %cmp, label %body, label %end
+body:
+  br label %end
+end:
+  %res = phi i64 [ %x, %entry ], [ 255, %body ]
+  ret i64 %res
+}
+
+; TODO: %x either ule 15 or is masked with 15
+define i64 @limit_i64_ule_15(i64 %x) {
+; CHECK-LABEL: @limit_i64_ule_15(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 16
+; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 15
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 15
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp ule i64 %x, 15
+  br i1 %cmp, label %end, label %body
+body:
+  %mask = and i64 %x, 15
+  br label %end
+end:
+  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
+  %res = and i64 %x.mask, 15
+  ret i64 %res
+}
+
+; TODO: %x either uge 7 or is masked with 7
+define i64 @limit_i64_uge_7(i64 %x) {
+; CHECK-LABEL: @limit_i64_uge_7(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i64 [[X:%.*]], 6
+; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 7
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp uge i64 %x, 7
+  br i1 %cmp, label %body, label %end
+body:
+  %mask = and i64 %x, 7
+  br label %end
+end:
+  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
+  %res = and i64 %x.mask, 7
+  ret i64 %res
+}
+
+; TODO: %x either ult 8 or is masked with 7
+define i64 @limit_i64_ult_8(i64 %x) {
+; CHECK-LABEL: @limit_i64_ult_8(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i64 [[X:%.*]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[END:%.*]], label [[BODY:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 7
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp ult i64 %x, 8
+  br i1 %cmp, label %end, label %body
+body:
+  %mask = and i64 %x, 7
+  br label %end
+end:
+  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
+  %res = and i64 %x.mask, 7
+  ret i64 %res
+}
+
+; TODO: %x either ugt 8 or is masked with 7
+define i64 @limit_i64_ugt_8(i64 %x) {
+; CHECK-LABEL: @limit_i64_ugt_8(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i64 [[X:%.*]], 8
+; CHECK-NEXT:    br i1 [[CMP]], label [[BODY:%.*]], label [[END:%.*]]
+; CHECK:       body:
+; CHECK-NEXT:    [[MASK:%.*]] = and i64 [[X]], 7
+; CHECK-NEXT:    br label [[END]]
+; CHECK:       end:
+; CHECK-NEXT:    [[X_MASK:%.*]] = phi i64 [ [[X]], [[ENTRY:%.*]] ], [ [[MASK]], [[BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = and i64 [[X_MASK]], 7
+; CHECK-NEXT:    ret i64 [[RES]]
+;
+entry:
+  %cmp = icmp ugt i64 %x, 8
+  br i1 %cmp, label %body, label %end
+body:
+  %mask = and i64 %x, 7
+  br label %end
+end:
+  %x.mask = phi i64 [ %x, %entry ], [ %mask, %body ]
+  %res = and i64 %x.mask, 7
+  ret i64 %res
+}
+
+