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    copied!<p>What's amusing with this question is that it's just so compiler dependent. Using Clang/LLVM:</p> <pre><code>#include &lt;iostream&gt; using namespace std; inline int foo(int a) { return a &lt;&lt; 1; } struct Bar { int a; Bar(int x) : a(x) {} Bar baz() { return a &lt;&lt; 1; } }; void out(int x) __attribute__ ((noinline)); void out(int x) { cout &lt;&lt; x; } void out(Bar x) __attribute__ ((noinline)); void out(Bar x) { cout &lt;&lt; x.a; } void f1(int x) __attribute ((noinline)); void f1(int x) { out(foo(x)); } void f2(Bar b) __attribute ((noinline)); void f2(Bar b) { out(b.baz()); } int main(int argc, char** argv) { f1(argc); f2(argc); } </code></pre> <p>Gives <a href="http://llvm.org/demo/index.cgi" rel="nofollow">the following IR</a>:</p> <pre><code>define void @_Z3outi(i32 %x) uwtable noinline { %1 = tail call %"class.std::basic_ostream"* @_ZNSolsEi(%"class.std::basic_ostream"* @_ZSt4cout, i32 %x) ret void } define void @_Z3out3Bar(i32 %x.coerce) uwtable noinline { %1 = tail call %"class.std::basic_ostream"* @_ZNSolsEi(%"class.std::basic_ostream"* @_ZSt4cout, i32 %x.coerce) ret void } define void @_Z2f1i(i32 %x) uwtable noinline { %1 = shl i32 %x, 1 tail call void @_Z3outi(i32 %1) ret void } define void @_Z2f23Bar(i32 %b.coerce) uwtable noinline { %1 = shl i32 %b.coerce, 1 tail call void @_Z3out3Bar(i32 %1) ret void } </code></pre> <p>And unsurprisingly, the generated assembly is just identical:</p> <pre><code> .globl _Z2f1i .align 16, 0x90 .type _Z2f1i,@function _Z2f1i: # @_Z2f1i .Ltmp6: .cfi_startproc # BB#0: addl %edi, %edi jmp _Z3outi # TAILCALL .Ltmp7: .size _Z2f1i, .Ltmp7-_Z2f1i .Ltmp8: .cfi_endproc .Leh_func_end2: .globl _Z2f23Bar .align 16, 0x90 .type _Z2f23Bar,@function _Z2f23Bar: # @_Z2f23Bar .Ltmp9: .cfi_startproc # BB#0: addl %edi, %edi jmp _Z3out3Bar # TAILCALL .Ltmp10: .size _Z2f23Bar, .Ltmp10-_Z2f23Bar .Ltmp11: .cfi_endproc .Leh_func_end3: </code></pre> <p>Normally, as long as the methods on the class are inlined, the <code>this</code> parameter and references can be omitted easily. I don't quite see how gcc could mess this up.</p>
 

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