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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Implements a new block return optimization. It targets frame unwinding in the cases of returning from (nested) blocks like these:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>def foo<o:p></o:p></p><p class=MsoNormal> x.times do<o:p></o:p></p><p class=MsoNormal> y.times do<o:p></o:p></p><p class=MsoNormal> return<o:p></o:p></p><p class=MsoNormal> end<o:p></o:p></p><p class=MsoNormal> end<o:p></o:p></p><p class=MsoNormal>end<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>We were throwing an exception in such cases to unwind the block frames. This is unnecessary because we already handle other kinds of control-flow (retry) in call sites with a block (x.times and y.times in the example above). So adding one more check (for frame unwinding return) there enables us to not throw an exception and doesn’t slow down the fast path (no cross-frame control flow).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Removes an unnecessary allocation in dynamic call sites that dispatch to a Ruby method and take a block.<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo3'><![if !supportLists]><span style='mso-list:Ignore'>3)<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Adds targeted unit tests to increase code coverage of control flow constructs.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Tomas<o:p></o:p></p></div></body></html>