[PATCH] D144838: [SCCP] Correct the made changes behavior

[chenglin.bi via Phabricator via llvm-commits]

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For now in some code path, even if it can be removed we still set `MadeChanges` to true. This patch fix them to make sure the `MadeChanges` set to true only if it is really changed.


https://reviews.llvm.org/D144838

Files:
  llvm/lib/Transforms/IPO/SCCP.cpp
  llvm/lib/Transforms/Utils/SCCPSolver.cpp


Index: llvm/lib/Transforms/Utils/SCCPSolver.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SCCPSolver.cpp
+++ llvm/lib/Transforms/Utils/SCCPSolver.cpp
@@ -235,10 +235,8 @@
   for (Instruction &Inst : make_early_inc_range(BB)) {
     if (Inst.getType()->isVoidTy())
       continue;
-    if (tryToReplaceWithConstant(&Inst)) {
-      if (canRemoveInstruction(&Inst))
-        Inst.eraseFromParent();
-
+    if (tryToReplaceWithConstant(&Inst) && canRemoveInstruction(&Inst)) {
+      Inst.eraseFromParent();
       MadeChanges = true;
       ++InstRemovedStat;
     } else if (replaceSignedInst(*this, InsertedValues, Inst)) {
Index: llvm/lib/Transforms/IPO/SCCP.cpp
===================================================================
--- llvm/lib/Transforms/IPO/SCCP.cpp
+++ llvm/lib/Transforms/IPO/SCCP.cpp
@@ -212,10 +212,10 @@
         LLVM_DEBUG(dbgs() << "  BasicBlock Dead:" << BB);
         ++NumDeadBlocks;
 
-        MadeChanges = true;
-
-        if (&BB != &F.front())
+        if (&BB != &F.front()) {
+          MadeChanges = true;
           BlocksToErase.push_back(&BB);
+        }
         continue;
       }
 


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