diff --git a/src/asm.rs b/src/asm.rs
index 72d572465f4..b446843a106 100644
--- a/src/asm.rs
+++ b/src/asm.rs
@@ -694,10 +694,12 @@ fn reg_to_gcc(reg: InlineAsmRegOrRegClass) -> ConstraintOrRegister {
 fn dummy_output_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, reg: InlineAsmRegClass) -> Type<'gcc> {
     match reg {
         InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::reg) => cx.type_i32(),
-        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => unimplemented!(),
         InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg)
         | InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::vreg_low16) => {
-            unimplemented!()
+            cx.type_vector(cx.type_i64(), 2)
+        }
+        InlineAsmRegClass::AArch64(AArch64InlineAsmRegClass::preg) => {
+            unreachable!("clobber-only")
         }
         InlineAsmRegClass::Arm(ArmInlineAsmRegClass::reg) => cx.type_i32(),
         InlineAsmRegClass::Arm(ArmInlineAsmRegClass::sreg)
@@ -708,21 +710,13 @@ fn dummy_output_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, reg: InlineAsmRegCl
         InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg)
         | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low8)
         | InlineAsmRegClass::Arm(ArmInlineAsmRegClass::qreg_low4) => {
-            unimplemented!()
+            cx.type_vector(cx.type_i64(), 2)
         }
-        InlineAsmRegClass::Avr(_) => unimplemented!(),
-        InlineAsmRegClass::Bpf(_) => unimplemented!(),
         InlineAsmRegClass::Hexagon(HexagonInlineAsmRegClass::reg) => cx.type_i32(),
         InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::reg) => cx.type_i32(),
         InlineAsmRegClass::LoongArch(LoongArchInlineAsmRegClass::freg) => cx.type_f32(),
-        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => cx.type_i32(),
-        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => cx.type_i32(),
-        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => cx.type_i32(),
-        InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => cx.type_i32(),
-        InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => cx.type_f32(),
         InlineAsmRegClass::Mips(MipsInlineAsmRegClass::reg) => cx.type_i32(),
         InlineAsmRegClass::Mips(MipsInlineAsmRegClass::freg) => cx.type_f32(),
-        InlineAsmRegClass::Msp430(_) => unimplemented!(),
         InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg16) => cx.type_i16(),
         InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg32) => cx.type_i32(),
         InlineAsmRegClass::Nvptx(NvptxInlineAsmRegClass::reg64) => cx.type_i64(),
@@ -735,26 +729,43 @@ fn dummy_output_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, reg: InlineAsmRegCl
         }
         InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::reg) => cx.type_i32(),
         InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::freg) => cx.type_f32(),
-        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => cx.type_f32(),
+        InlineAsmRegClass::RiscV(RiscVInlineAsmRegClass::vreg) => {
+            unreachable!("clobber-only")
+        }
         InlineAsmRegClass::X86(X86InlineAsmRegClass::reg)
         | InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_abcd) => cx.type_i32(),
         InlineAsmRegClass::X86(X86InlineAsmRegClass::reg_byte) => cx.type_i8(),
-        InlineAsmRegClass::X86(X86InlineAsmRegClass::mmx_reg) => unimplemented!(),
         InlineAsmRegClass::X86(X86InlineAsmRegClass::xmm_reg)
         | InlineAsmRegClass::X86(X86InlineAsmRegClass::ymm_reg)
         | InlineAsmRegClass::X86(X86InlineAsmRegClass::zmm_reg) => cx.type_f32(),
-        InlineAsmRegClass::X86(X86InlineAsmRegClass::x87_reg) => unimplemented!(),
         InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg) => cx.type_i16(),
-        InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg0) => cx.type_i16(),
-        InlineAsmRegClass::X86(X86InlineAsmRegClass::tmm_reg) => unimplemented!(),
-        InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => cx.type_i32(),
-        InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
-            bug!("LLVM backend does not support SPIR-V")
+        InlineAsmRegClass::X86(X86InlineAsmRegClass::x87_reg)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::mmx_reg)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::kreg0)
+        | InlineAsmRegClass::X86(X86InlineAsmRegClass::tmm_reg) => {
+            unreachable!("clobber-only")
         }
+        InlineAsmRegClass::Wasm(WasmInlineAsmRegClass::local) => cx.type_i32(),
+        InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::reg) => cx.type_i64(),
+        InlineAsmRegClass::Bpf(BpfInlineAsmRegClass::wreg) => cx.type_i32(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg) => cx.type_i8(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_upper) => cx.type_i8(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_pair) => cx.type_i16(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_iw) => cx.type_i16(),
+        InlineAsmRegClass::Avr(AvrInlineAsmRegClass::reg_ptr) => cx.type_i16(),
         InlineAsmRegClass::S390x(
             S390xInlineAsmRegClass::reg | S390xInlineAsmRegClass::reg_addr,
         ) => cx.type_i32(),
         InlineAsmRegClass::S390x(S390xInlineAsmRegClass::freg) => cx.type_f64(),
+        InlineAsmRegClass::Msp430(Msp430InlineAsmRegClass::reg) => cx.type_i16(),
+        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_addr) => cx.type_i32(),
+        InlineAsmRegClass::M68k(M68kInlineAsmRegClass::reg_data) => cx.type_i32(),
+        InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::reg) => cx.type_i32(),
+        InlineAsmRegClass::CSKY(CSKYInlineAsmRegClass::freg) => cx.type_f32(),
+        InlineAsmRegClass::SpirV(SpirVInlineAsmRegClass::reg) => {
+            bug!("GCC backend does not support SPIR-V")
+        }
         InlineAsmRegClass::Err => unreachable!(),
     }
 }