diff --git a/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp b/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp
--- a/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/InlineAsmLowering.cpp
@@ -525,8 +525,22 @@
 
       unsigned Flag = InlineAsm::getFlagWord(InlineAsm::Kind_RegUse, NumRegs);
       Inst.addImm(Flag);
-      MIRBuilder.buildCopy(OpInfo.Regs[0], SourceRegs[0]);
-      Inst.addReg(OpInfo.Regs[0]);
+
+      // We might need to extend the input registers to fit the register class
+      Register TargetReg = OpInfo.Regs[0];
+      Register InputReg = SourceRegs[0];
+
+      unsigned TargetSize = TRI->getRegSizeInBits(TargetReg, *MRI);
+      unsigned InputSize = MRI->getType(InputReg).getSizeInBits();
+
+      if (InputSize < TargetSize) {
+        Register ScratchReg =
+            MRI->createGenericVirtualRegister(LLT::scalar(TargetSize));
+        InputReg = MIRBuilder.buildAnyExt(ScratchReg, InputReg).getReg(0);
+      }
+
+      MIRBuilder.buildCopy(TargetReg, InputReg);
+      Inst.addReg(TargetReg);
       break;
     }
 
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/irtranslator-inline-asm.ll b/llvm/test/CodeGen/AArch64/GlobalISel/irtranslator-inline-asm.ll
--- a/llvm/test/CodeGen/AArch64/GlobalISel/irtranslator-inline-asm.ll
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/irtranslator-inline-asm.ll
@@ -199,6 +199,18 @@
   ret i8 %0
 }
 
+define void @test_input_register_extend() {
+  ; CHECK-LABEL: name: test_input_register_extend
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK:   [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 42
+  ; CHECK:   [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[C]](s8)
+  ; CHECK:   [[COPY:%[0-9]+]]:gpr32common = COPY [[ANYEXT]](s32)
+  ; CHECK:   INLINEASM &"mov x0, $0", 1 /* sideeffect attdialect */, 9 /* reguse */, [[COPY]]
+  ; CHECK:   RET_ReallyLR
+  call void asm sideeffect "mov x0, $0", "r"(i8 42)
+  ret void
+}
+
 define i32 @test_memory_constraint(i32* %a) nounwind {
   ; CHECK-LABEL: name: test_memory_constraint
   ; CHECK: bb.1 (%ir-block.0):