[llvm] [CodeGen] Restore MachineBlockPlacement block ordering (PR #99351)

[David Li via llvm-commits]

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@@ -2614,18 +2614,21 @@ MachineBlockPlacement::collectLoopBlockSet(const MachineLoop &L) {
         LoopFreq += MBFI->getBlockFreq(LoopPred) *
                     MBPI->getEdgeProbability(LoopPred, L.getHeader());
 
-    for (MachineBasicBlock *LoopBB : L.getBlocks()) {
-      if (LoopBlockSet.count(LoopBB))
+    for (auto &MBB : *F) {
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david-xl wrote:

IIUC, the original patch avoids traversing the full function body to avoid the high complexity in compile time. This will probably restore the old behavior.



https://github.com/llvm/llvm-project/pull/99351