diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -620,8 +620,8 @@
 }
 
 bool WebAssemblyTargetLowering::isVectorLoadExtDesirable(SDValue ExtVal) const {
-  MVT ExtT = ExtVal.getSimpleValueType();
-  MVT MemT = cast<LoadSDNode>(ExtVal->getOperand(0))->getSimpleValueType(0);
+  EVT ExtT = ExtVal.getValueType();
+  EVT MemT = cast<LoadSDNode>(ExtVal->getOperand(0))->getValueType(0);
   return (ExtT == MVT::v8i16 && MemT == MVT::v8i8) ||
          (ExtT == MVT::v4i32 && MemT == MVT::v4i16) ||
          (ExtT == MVT::v2i64 && MemT == MVT::v2i32);
diff --git a/llvm/test/CodeGen/WebAssembly/pr47375.ll b/llvm/test/CodeGen/WebAssembly/pr47375.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/pr47375.ll
@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+; Regression test for pr47375, in which an assertion was triggering
+; because WebAssemblyTargetLowering::isVectorLoadExtDesirable was
+; improperly assuming the use of simple value types.
+
+define void @sext_vec() {
+; CHECK-LABEL: sext_vec:
+; CHECK:         .functype sext_vec () -> ()
+; CHECK-NEXT:    .local i32
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    i32.load8_u 0
+; CHECK-NEXT:    local.set 0
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    i32.const 0
+; CHECK-NEXT:    i32.store8 0
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    i32.const 7
+; CHECK-NEXT:    i32.shl
+; CHECK-NEXT:    i32.or
+; CHECK-NEXT:    i32.const 7175
+; CHECK-NEXT:    i32.and
+; CHECK-NEXT:    i32.store16 0
+; CHECK-NEXT:    # fallthrough-return
+  %L1 = load <2 x i3>, <2 x i3>* undef, align 2
+  %zext = zext <2 x i3> %L1 to <2 x i10>
+  store <2 x i10> %zext, <2 x i10>* undef, align 4
+  ret void
+}