[PATCH] D31704: [BPI] NFC: reorder ifs to bail out earlier

[Serguei Katkov via Phabricator via llvm-commits]

skatkov updated this revision to Diff 94652.

https://reviews.llvm.org/D31704

Files:
  lib/Analysis/BranchProbabilityInfo.cpp


Index: lib/Analysis/BranchProbabilityInfo.cpp
===================================================================
--- lib/Analysis/BranchProbabilityInfo.cpp
+++ lib/Analysis/BranchProbabilityInfo.cpp
@@ -205,7 +205,11 @@
 /// unreachable-terminated block as extremely unlikely.
 bool BranchProbabilityInfo::calcUnreachableHeuristics(const BasicBlock *BB) {
   const TerminatorInst *TI = BB->getTerminator();
-  if (TI->getNumSuccessors() == 0)
+  assert(TI->getNumSuccessors() > 1);
+
+  // Return false here so that edge weights for InvokeInst could be decided
+  // in calcInvokeHeuristics().
+  if (isa<InvokeInst>(TI))
     return false;
 
   SmallVector<unsigned, 4> UnreachableEdges;
@@ -217,14 +221,8 @@
     else
       ReachableEdges.push_back(I.getSuccessorIndex());
 
-  // Skip probabilities if this block has a single successor or if all were
-  // reachable.
-  if (TI->getNumSuccessors() == 1 || UnreachableEdges.empty())
-    return false;
-
-  // Return false here so that edge weights for InvokeInst could be decided
-  // in calcInvokeHeuristics().
-  if (isa<InvokeInst>(TI))
+  // Skip probabilities if all were reachable.
+  if (UnreachableEdges.empty())
     return false;
 
   if (ReachableEdges.empty()) {
@@ -252,8 +250,7 @@
 // ignored.
 bool BranchProbabilityInfo::calcMetadataWeights(const BasicBlock *BB) {
   const TerminatorInst *TI = BB->getTerminator();
-  if (TI->getNumSuccessors() <= 1)
-    return false;
+  assert(TI->getNumSuccessors() > 1);
   if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
     return false;
 
@@ -341,7 +338,11 @@
 /// Return false, otherwise.
 bool BranchProbabilityInfo::calcColdCallHeuristics(const BasicBlock *BB) {
   const TerminatorInst *TI = BB->getTerminator();
-  if (TI->getNumSuccessors() == 0)
+  assert(TI->getNumSuccessors() > 1);
+
+  // Return false here so that edge weights for InvokeInst could be decided
+  // in calcInvokeHeuristics().
+  if (isa<InvokeInst>(TI))
     return false;
 
   // Determine which successors are post-dominated by a cold block.
@@ -353,13 +354,8 @@
     else
       NormalEdges.push_back(I.getSuccessorIndex());
 
-  // Return false here so that edge weights for InvokeInst could be decided
-  // in calcInvokeHeuristics().
-  if (isa<InvokeInst>(TI))
-    return false;
-
-  // Skip probabilities if this block has a single successor.
-  if (TI->getNumSuccessors() == 1 || ColdEdges.empty())
+  // Skip probabilities if no cold edges.
+  if (ColdEdges.empty())
     return false;
 
   if (NormalEdges.empty()) {
@@ -742,6 +738,9 @@
     DEBUG(dbgs() << "Computing probabilities for " << BB->getName() << "\n");
     updatePostDominatedByUnreachable(BB);
     updatePostDominatedByColdCall(BB);
+    // If there is no at least two successors, no sense to set probability.
+    if (BB->getTerminator()->getNumSuccessors() < 2)
+      continue;
     if (calcMetadataWeights(BB))
       continue;
     if (calcUnreachableHeuristics(BB))


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D31704.94652.patch
Type: text/x-patch
Size: 2945 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170410/c98b38c4/attachment.bin>