<div dir="ltr"><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">Hi.</span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt"><br></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">I have this nested loop. When loop@Depth3 is processed, BB#193 is the exiting block. And when loop@Depth2 is processed, the loop is rotated w.r.t BB#193 because PreferredLoopExit is not cleared. This does not seem right to me as BB#193 does not even exit loop@Depth2. Should not we clear <span></span></span><span style="font-size:14.6667px">PreferredLoopExit everytime we process a new loop ?</span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt"> </span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">BB#193: derived from LLVM BB %cleanup.i.i781<span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">    Live Ins: %RAX %RBP %RBX %RSI %R9 %R10 %R11 %R13 %R14 %R15<span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">    Predecessors according to CFG: BB#192<span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">        %RBX<def,tied1> = ADD64ri8 %RBX<kill,tied0>, 8, %EFLAGS<imp-def,dead><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">        %RBP<def,tied1> = ADD64ri8 %RBP<kill,tied0>, 8, %EFLAGS<imp-def,dead><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">        CMP64rr %RBX, %R15, %EFLAGS<imp-def><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">        JB_1 <BB#192>, %EFLAGS<imp-use><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">        JMP_1 <BB#174><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">    Successors according to CFG: BB#192(0x7fef9fcb / 0x80000000 = 99.95%) BB#174(0x00106035 / 0x80000000 = 0.05%)<span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt"> </span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">Loop at depth 2 containing: BB#191<header>,BB#192,BB#182,BB#193,BB#174,BB#175,BB#176,BB#177,BB#178,BB#179,BB#180,BB#181,BB#183,BB#187<exiting>,BB#184,BB#185,BB#186<exiting>,BB#188<exiting>,BB#189<exiting>,BB#190<latch><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0);text-indent:9pt"><span style="font-size:11pt">Loop at depth 3 containing: BB#192<header><exiting>,BB#193<latch><exiting><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt"> </span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">Thanks<span class="gmail-Apple-converted-space"> </span><span></span></span></p><p class="MsoNormal" style="margin:0in 0in 0.0001pt;font-size:12pt;font-family:Calibri,sans-serif;color:rgb(0,0,0)"><span style="font-size:11pt">-Xin</span></p><div><br></div>-- <br><div class="gmail_signature">Software Engineer - Compiler Toolchain<br>Employee of Facebook Inc.</div>
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