[PATCH] D18762: Add Aggressive Control Dead Code Elimination

[David Callahan via llvm-commits]

david2050 marked 10 inline comments as done.
david2050 added a comment.

Thanks for the review


================
Comment at: lib/Transforms/IPO/PassManagerBuilder.cpp:321-322
@@ +320,4 @@
+    MPM.add(createAggressiveControlDCEPass());  // Delete dead instructions
+  }
+  else {
+    MPM.add(createAggressiveDCEPass());         // Delete dead instructions
----------------
majnemer wrote:
> Please format this appropriately.
I assume this means removing the braces.

================
Comment at: lib/Transforms/Scalar/ACDCE.cpp:508-513
@@ +507,8 @@
+bool AggressiveControlDCE::alwaysLive(Instruction &I) const {
+  if (I.isEHPad() || I.mayHaveSideEffects()) {
+    if (isInstrumentsConstant(I)) {
+      return false;
+    }
+    return true;
+  }
+  if (!isa<TerminatorInst>(I)) {
----------------
majnemer wrote:
> Why are EHPads always considered live?
I cribbed the condition from the existing ADCE pass. I assumed that it would be impossible to remove the corresponding invoke so simplest to just keep the operation live.


http://reviews.llvm.org/D18762