On Mon, Jun 3, 2013 at 9:41 AM, David Blaikie <span dir="ltr"><<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="HOEnZb"><div class="h5">On Mon, Jun 3, 2013 at 12:13 AM, Richard Smith<br>
<<a href="mailto:richard-llvm@metafoo.co.uk">richard-llvm@metafoo.co.uk</a>> wrote:<br>
> Author: rsmith<br>
> Date: Mon Jun 3 02:13:35 2013<br>
> New Revision: 183095<br>
><br>
> URL: <a href="http://llvm.org/viewvc/llvm-project?rev=183095&view=rev" target="_blank">http://llvm.org/viewvc/llvm-project?rev=183095&view=rev</a><br>
> Log:<br>
> Do not walk through member-accesses on bitfields when looking for the object<br>
> which is lifetime-extended by a reference binding. An additional temporary is<br>
> created for such a bitfield access (although we have no explicit AST<br>
> representation for it).<br>
><br>
> Modified:<br>
> cfe/trunk/lib/AST/Expr.cpp<br>
> cfe/trunk/test/CodeGenCXX/temporaries.cpp<br>
><br>
> Modified: cfe/trunk/lib/AST/Expr.cpp<br>
> URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=183095&r1=183094&r2=183095&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Expr.cpp?rev=183095&r1=183094&r2=183095&view=diff</a><br>
> ==============================================================================<br>
> --- cfe/trunk/lib/AST/Expr.cpp (original)<br>
> +++ cfe/trunk/lib/AST/Expr.cpp Mon Jun 3 02:13:35 2013<br>
> @@ -76,9 +76,11 @@ const Expr *Expr::skipRValueSubobjectAdj<br>
> if (!ME->isArrow() && ME->getBase()->isRValue()) {<br>
> assert(ME->getBase()->getType()->isRecordType());<br>
> if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {<br>
> - E = ME->getBase();<br>
> - Adjustments.push_back(SubobjectAdjustment(Field));<br>
> - continue;<br>
> + if (!Field->isBitField()) {<br>
> + E = ME->getBase();<br>
> + Adjustments.push_back(SubobjectAdjustment(Field));<br>
> + continue;<br>
> + }<br>
> }<br>
> }<br>
> } else if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {<br>
><br>
> Modified: cfe/trunk/test/CodeGenCXX/temporaries.cpp<br>
> URL: <a href="http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/temporaries.cpp?rev=183095&r1=183094&r2=183095&view=diff" target="_blank">http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/temporaries.cpp?rev=183095&r1=183094&r2=183095&view=diff</a><br>
> ==============================================================================<br>
> --- cfe/trunk/test/CodeGenCXX/temporaries.cpp (original)<br>
> +++ cfe/trunk/test/CodeGenCXX/temporaries.cpp Mon Jun 3 02:13:35 2013<br>
> @@ -604,3 +604,15 @@ namespace BindToSubobject {<br>
> // CHECK: store i32* {{.*}}, i32** @_ZN15BindToSubobject1dE, align 8<br>
> int &&d = (B().a).*h();<br>
> }<br>
> +<br>
> +namespace Bitfield {<br>
> + struct S { int a : 5; ~S(); };<br>
> +<br>
> + // Do not lifetime extend the S() temporary here.<br>
> +Â // CHECK: alloca<br>
<br>
</div></div>Did some kind of interesting unicode sneak in here?</blockquote><div><br></div><div>Apparently so, thanks! Fixed in r183116.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="HOEnZb"><div class="h5">
> +Â // CHECK: call {{.*}}memset<br>
> +Â // CHECK: store i32 {{.*}}, i32* @_ZGRN8Bitfield1rE, align 4<br>
> + // CHECK: call void @_ZN8Bitfield1SD1<br>
> +Â // CHECK: store i32* @_ZGRN8Bitfield1rE, i32** @_ZN8Bitfield1rE, align 8<br>
> + int &&r = S().a;<br>
> +}<br>
><br>
><br>
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</div></div></blockquote></div><br>