diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -9772,15 +9772,19 @@
   }
 
   // If there isn't a 16-bit med3 operation, convert to 32-bit.
-  MVT NVT = MVT::i32;
-  unsigned ExtOp = Signed ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
+  if (VT == MVT::i16) {
+    MVT NVT = MVT::i32;
+    unsigned ExtOp = Signed ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
 
-  SDValue Tmp1 = DAG.getNode(ExtOp, SL, NVT, Op0->getOperand(0));
-  SDValue Tmp2 = DAG.getNode(ExtOp, SL, NVT, Op0->getOperand(1));
-  SDValue Tmp3 = DAG.getNode(ExtOp, SL, NVT, Op1);
+    SDValue Tmp1 = DAG.getNode(ExtOp, SL, NVT, Op0->getOperand(0));
+    SDValue Tmp2 = DAG.getNode(ExtOp, SL, NVT, Op0->getOperand(1));
+    SDValue Tmp3 = DAG.getNode(ExtOp, SL, NVT, Op1);
 
-  SDValue Med3 = DAG.getNode(Med3Opc, SL, NVT, Tmp1, Tmp2, Tmp3);
-  return DAG.getNode(ISD::TRUNCATE, SL, VT, Med3);
+    SDValue Med3 = DAG.getNode(Med3Opc, SL, NVT, Tmp1, Tmp2, Tmp3);
+    return DAG.getNode(ISD::TRUNCATE, SL, VT, Med3);
+  }
+
+  return SDValue();
 }
 
 static ConstantFPSDNode *getSplatConstantFP(SDValue Op) {
diff --git a/llvm/test/CodeGen/AMDGPU/smed3.ll b/llvm/test/CodeGen/AMDGPU/smed3.ll
--- a/llvm/test/CodeGen/AMDGPU/smed3.ll
+++ b/llvm/test/CodeGen/AMDGPU/smed3.ll
@@ -80,6 +80,19 @@
   ret void
 }
 
+; Regression test for performIntMed3ImmCombine extending arguments to 32 bit
+; which failed for 64 bit arguments. Previously asserted / crashed.
+; GCN-LABEL: {{^}}test_intMed3ImmCombine_no_32bit_extend:
+; GCN: v_cmp_lt_i64
+; GCN: v_cmp_gt_i64
+define i64 @test_intMed3ImmCombine_no_32bit_extend(i64 %x) {
+  %smax = call i64 @llvm.smax.i64(i64 %x, i64 -2)
+  %smin = call i64 @llvm.smin.i64(i64 %smax, i64 2)
+  ret i64 %smin
+}
+declare i64 @llvm.smax.i64(i64, i64)
+declare i64 @llvm.smin.i64(i64, i64)
+
 ; GCN-LABEL: {{^}}v_test_smed3_r_i_i_i16:
 ; SICIVI: v_med3_i32 v{{[0-9]+}}, v{{[0-9]+}}, 12, 17
 ; GFX9: v_med3_i16 v{{[0-9]+}}, v{{[0-9]+}}, 12, 17