[PATCH] D15857: [InstCombine] Defend against worst-case exponential execution time

[David Majnemer via llvm-commits]

majnemer added inline comments.

================
Comment at: lib/CodeGen/CodeGenPrepare.cpp:5241-5250
@@ -5228,1 +5240,12 @@
 
+  bool MadeBitReverse = true;
+  while (MadeBitReverse) {
+    MadeBitReverse = false;
+    for (auto &I : reverse(BB)) {
+      if (makeBitReverse(I)) {
+        MadeBitReverse = MadeChange = true;
+        break;
+      }
+    }
+  }
+  
----------------
Should we bother doing this on targets which can't lower biterverse to anything good?


Repository:
  rL LLVM

http://reviews.llvm.org/D15857