diff --git a/lib/CodeGen/CodeGenPrepare.cpp b/lib/CodeGen/CodeGenPrepare.cpp
index d5039b2e851..8b1c3ad8eab 100644
--- a/lib/CodeGen/CodeGenPrepare.cpp
+++ b/lib/CodeGen/CodeGenPrepare.cpp
@@ -662,10 +662,13 @@ SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
     if (!ISDOpcode)
       continue;
 
-    // If the use is actually a legal node, there will not be an implicit
-    // truncate.
+    // If the use is actually a legal node, there will not be an
+    // implicit truncate.
+    // FIXME: always querying the result type is just an
+    // approximation; some nodes' legality is determined by the
+    // operand or other means. There's no good way to find out though.
     if (TLI.isOperationLegalOrCustom(ISDOpcode,
-                                     EVT::getEVT(TruncUser->getType())))
+                                     EVT::getEVT(TruncUser->getType(), true)))
       continue;
 
     // Don't bother for PHI nodes.
diff --git a/test/Transforms/CodeGenPrepare/AArch64/lit.local.cfg b/test/Transforms/CodeGenPrepare/AArch64/lit.local.cfg
new file mode 100644
index 00000000000..cec29af5bbe
--- /dev/null
+++ b/test/Transforms/CodeGenPrepare/AArch64/lit.local.cfg
@@ -0,0 +1,3 @@
+if not 'AArch64' in config.root.targets:
+    config.unsupported = True
+
diff --git a/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll b/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll
new file mode 100644
index 00000000000..1a0878007b6
--- /dev/null
+++ b/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll
@@ -0,0 +1,17 @@
+; RUN: opt -S -codegenprepare -mtriple=arm64-apple-ios7.0 %s | FileCheck %s
+
+%foo = type { i8 }
+
+define %foo @test_merge(i32 %in) {
+; CHECK-LABEL: @test_merge
+
+  ; CodeGenPrepare was requesting the EVT for { i8 } to determine
+  ; whether the insertvalue user of the trunc was legal. This
+  ; asserted.
+
+; CHECK: insertvalue %foo undef, i8 %byte, 0
+  %lobit = lshr i32 %in, 31
+  %byte = trunc i32 %lobit to i8
+  %struct = insertvalue %foo undef, i8 %byte, 0
+  ret %"foo" %struct
+}