Reapply "[CGP] Check for existing inttotpr before creating new one"

Original commit: r351582

llvm-svn: 351618

1 files changed, 17 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index c35f8666fa3..e33178c961d 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -4664,13 +4664,26 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
     // will look through it and provide only the integer value. In that case,
     // use it here.
     if (!DL->isNonIntegralPointerType(Addr->getType())) {
+      const auto getResultPtr = [MemoryInst, Addr,
+                                 &Builder](Value *Reg) -> Value * {
+        BasicBlock *BB = MemoryInst->getParent();
+        for (User *U : Reg->users())
+          if (auto *I2P = dyn_cast<IntToPtrInst>(U))
+            if (I2P->getType() == Addr->getType() && I2P->getParent() == BB) {
+              if (isa<Instruction>(Reg) &&
+                  cast<Instruction>(Reg)->getParent() == BB)
+                I2P->moveAfter(cast<Instruction>(Reg));
+              else
+                I2P->moveBefore(BB->getFirstNonPHI());
+              return I2P;
+            }
+        return Builder.CreateIntToPtr(Reg, Addr->getType(), "sunkaddr");
+      };
       if (!ResultPtr && AddrMode.BaseReg) {
-        ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(),
-                                           "sunkaddr");
+        ResultPtr = getResultPtr(AddrMode.BaseReg);
         AddrMode.BaseReg = nullptr;
       } else if (!ResultPtr && AddrMode.Scale == 1) {
-        ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(),
-                                           "sunkaddr");
+        ResultPtr = getResultPtr(AddrMode.ScaledReg);
         AddrMode.Scale = 0;
       }
     }