[PATCH] D136297: llvm-reduce: Skip reducing branches that already have the condition to set

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added reviewers: aeubanks, regehr, lebedev.ri.
Herald added a project: All.
arsenm requested review of this revision.
Herald added a subscriber: wdng.
Herald added a project: LLVM.

This should reduce the number of steps when resuming a
reduction.


https://reviews.llvm.org/D136297

Files:
  llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp


Index: llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp
===================================================================
--- llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp
+++ llvm/tools/llvm-reduce/deltas/ReduceUsingSimplifyCFG.cpp
@@ -39,7 +39,22 @@
   for (auto &F : M) {
     for (auto &BB : F) {
       auto *BR = dyn_cast<BranchInst>(BB.getTerminator());
-      if (!BR || !BR->isConditional() || O.shouldKeep())
+      if (!BR || !BR->isConditional())
+        continue;
+
+      // Skip cases that already have the value we're going to set this to.
+      ConstantInt *Cond = dyn_cast<ConstantInt>(BR->getCondition());
+      if (Cond) {
+        if (Direction) {
+          if (Cond->isOne())
+            continue;
+        } else {
+          if (Cond->isZero())
+            continue;
+        }
+      }
+
+      if (O.shouldKeep())
         continue;
 
       if (Direction)


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