1 files changed, 26 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
index 6c6351c70e3a..35739c3b9a21 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
@@ -299,6 +299,29 @@ Instruction *InstCombinerImpl::foldIntegerTypedPHI(PHINode &PN) {
                                           IntToPtr->getOperand(0)->getType());
 }
 
+// Remove RoundTrip IntToPtr/PtrToInt Cast on PHI-Operand and
+// fold Phi-operand to bitcast.
+Instruction *InstCombinerImpl::foldPHIArgIntToPtrToPHI(PHINode &PN) {
+  // convert ptr2int ( phi[ int2ptr(ptr2int(x))] ) --> ptr2int ( phi [ x ] )
+  // Make sure all uses of phi are ptr2int.
+  if (!all_of(PN.users(), [](User *U) { return isa<PtrToIntInst>(U); }))
+    return nullptr;
+
+  // Iterating over all operands to check presence of target pointers for
+  // optimization.
+  bool OperandWithRoundTripCast = false;
+  for (unsigned OpNum = 0; OpNum != PN.getNumIncomingValues(); ++OpNum) {
+    if (auto *NewOp =
+            simplifyIntToPtrRoundTripCast(PN.getIncomingValue(OpNum))) {
+      PN.setIncomingValue(OpNum, NewOp);
+      OperandWithRoundTripCast = true;
+    }
+  }
+  if (!OperandWithRoundTripCast)
+    return nullptr;
+  return &PN;
+}
+
 /// If we have something like phi [insertvalue(a,b,0), insertvalue(c,d,0)],
 /// turn this into a phi[a,c] and phi[b,d] and a single insertvalue.
 Instruction *
@@ -1306,6 +1329,9 @@ Instruction *InstCombinerImpl::visitPHINode(PHINode &PN) {
   if (Instruction *Result = foldPHIArgZextsIntoPHI(PN))
     return Result;
 
+  if (Instruction *Result = foldPHIArgIntToPtrToPHI(PN))
+    return Result;
+
   // If all PHI operands are the same operation, pull them through the PHI,
   // reducing code size.
   if (isa<Instruction>(PN.getIncomingValue(0)) &&