diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 3e7eafd756e8..5e766d8e0ff8 100644
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -2460,47 +2460,6 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
     return Si;
   }
 
-  // Instrument:
-  //     switch i32 %Val, label %else [ i32 0, label %A
-  //                                    i32 1, label %B
-  //                                    i32 2, label %C ]
-  //
-  // Typically, the switch input value (%Val) is fully initialized.
-  //
-  // Sometimes the compiler may convert (icmp + br) into a switch statement.
-  // MSan allows icmp eq/ne with partly initialized inputs to still result in a
-  // fully initialized output, if there exists a bit that is initialized in
-  // both inputs with a differing value. For compatibility, we support this in
-  // the switch instrumentation as well. Note that this edge case only applies
-  // if the switch input value does not match *any* of the cases (matching any
-  // of the cases requires an exact, fully initialized match).
-  //
-  //     ShadowCases =   0
-  //                   | propagateEqualityComparison(Val, 0)
-  //                   | propagateEqualityComparison(Val, 1)
-  //                   | propagateEqualityComparison(Val, 2))
-  void visitSwitchInst(SwitchInst &SI) {
-    IRBuilder<> IRB(&SI);
-
-    Value *Val = SI.getCondition();
-    Value *ShadowVal = getShadow(Val);
-
-    Value *ShadowCases = nullptr;
-    for (auto Case : SI.cases()) {
-      Value *Comparator = Case.getCaseValue();
-      Value *ComparisonShadow = propagateEqualityComparison(
-          IRB, Val, Comparator, ShadowVal, getShadow(Comparator));
-
-      if (ShadowCases)
-        ShadowCases = IRB.CreateOr(ShadowCases, ComparisonShadow);
-      else
-        ShadowCases = ComparisonShadow;
-    }
-
-    if (ShadowCases)
-      insertCheckShadow(ShadowCases, getOrigin(Val), &SI);
-  }
-
   // Vector manipulation.
   void visitExtractElementInst(ExtractElementInst &I) {
     insertCheckShadowOf(I.getOperand(1), &I);
diff --git a/llvm/test/Instrumentation/MemorySanitizer/switch-icmp.ll b/llvm/test/Instrumentation/MemorySanitizer/switch-icmp.ll
index 08e56516ff5b..08c9a5a62feb 100644
--- a/llvm/test/Instrumentation/MemorySanitizer/switch-icmp.ll
+++ b/llvm/test/Instrumentation/MemorySanitizer/switch-icmp.ll
@@ -8,10 +8,9 @@
 ; uninitialized, if a bit is initialized in both inputs but has a different
 ; value.
 ;
-; If switch has a partly uninitialized input, but it is possible to rule out
-; matching any of the cases, it will use the default case instead of reporting
-; use-of-uninitialized memory. This is equivalent to if the switch was replaced
-; by a series of (icmp eq + br).
+; TODO: since the compiler/optimizer may freely choose between (icmp eq + br)
+;       vs. switch, MSan's switch instrumentation also needs to be able to
+;       handle partly-uninitialized inputs.
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
@@ -21,22 +20,8 @@ define i64 @switch_test(i32 %wii) sanitize_memory {
 ; CHECK-SAME: i32 [[WII:%.*]]) #[[ATTR0:[0-9]+]] {
 ; CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr @__msan_param_tls, align 8
 ; CHECK-NEXT:    call void @llvm.donothing()
-; CHECK-NEXT:    [[TMP3:%.*]] = xor i32 [[WII]], 42
-; CHECK-NEXT:    [[TMP4:%.*]] = or i32 [[TMP1]], 0
-; CHECK-NEXT:    [[TMP5:%.*]] = icmp ne i32 [[TMP4]], 0
-; CHECK-NEXT:    [[TMP6:%.*]] = xor i32 [[TMP4]], -1
-; CHECK-NEXT:    [[TMP7:%.*]] = and i32 [[TMP6]], [[TMP3]]
-; CHECK-NEXT:    [[TMP8:%.*]] = icmp eq i32 [[TMP7]], 0
-; CHECK-NEXT:    [[_MSPROP_ICMP:%.*]] = and i1 [[TMP5]], [[TMP8]]
-; CHECK-NEXT:    [[TMP9:%.*]] = xor i32 [[WII]], 43
-; CHECK-NEXT:    [[TMP10:%.*]] = or i32 [[TMP1]], 0
-; CHECK-NEXT:    [[TMP11:%.*]] = icmp ne i32 [[TMP10]], 0
-; CHECK-NEXT:    [[TMP12:%.*]] = xor i32 [[TMP10]], -1
-; CHECK-NEXT:    [[TMP13:%.*]] = and i32 [[TMP12]], [[TMP9]]
-; CHECK-NEXT:    [[TMP14:%.*]] = icmp eq i32 [[TMP13]], 0
-; CHECK-NEXT:    [[_MSPROP_ICMP1:%.*]] = and i1 [[TMP11]], [[TMP14]]
-; CHECK-NEXT:    [[TMP15:%.*]] = or i1 [[_MSPROP_ICMP]], [[_MSPROP_ICMP1]]
-; CHECK-NEXT:    br i1 [[TMP15]], label %[[BB2:.*]], label %[[BB3:.*]], !prof [[PROF1:![0-9]+]]
+; CHECK-NEXT:    [[_MSCMP:%.*]] = icmp ne i32 [[TMP1]], 0
+; CHECK-NEXT:    br i1 [[_MSCMP]], label %[[BB2:.*]], label %[[BB3:.*]], !prof [[PROF1:![0-9]+]]
 ; CHECK:       [[BB2]]:
 ; CHECK-NEXT:    call void @__msan_warning_noreturn() #[[ATTR3:[0-9]+]]
 ; CHECK-NEXT:    unreachable