3 files changed, 37 insertions, 1 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
index db79eed709e..e32777f57da 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
@@ -118,7 +118,7 @@ EnableA53Fix835769("aarch64-fix-cortex-a53-835769", cl::Hidden,
 static cl::opt<bool>
     EnableAddressTypePromotion("aarch64-enable-type-promotion", cl::Hidden,
                                cl::desc("Enable the type promotion pass"),
-                               cl::init(true));
+                               cl::init(false));
 
 static cl::opt<bool>
     EnableGEPOpt("aarch64-enable-gep-opt", cl::Hidden,
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index be14a832265..77ca4c6b087 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -626,6 +626,38 @@ bool AArch64TTIImpl::getTgtMemIntrinsic(IntrinsicInst *Inst,
   return true;
 }
 
+/// See if \p I should be considered for address type promotion. We check if \p
+/// I is a sext with right type and used in memory accesses. If it used in a
+/// "complex" getelementptr, we allow it to be promoted without finding other
+/// sext instructions that sign extended the same initial value. A getelementptr
+/// is considered as "complex" if it has more than 2 operands.
+bool AArch64TTIImpl::shouldConsiderAddressTypePromotion(
+    const Instruction &I, bool &AllowPromotionWithoutCommonHeader) {
+  bool Considerable = false;
+  AllowPromotionWithoutCommonHeader = false;
+  if (!isa<SExtInst>(&I))
+    return false;
+  Type *ConsideredSExtType =
+      Type::getInt64Ty(I.getParent()->getParent()->getContext());
+  if (I.getType() != ConsideredSExtType)
+    return false;
+  // See if the sext is the one with the right type and used in at least one
+  // GetElementPtrInst.
+  for (const User *U : I.users()) {
+    if (const GetElementPtrInst *GEPInst = dyn_cast<GetElementPtrInst>(U)) {
+      Considerable = true;
+      // A getelementptr is considered as "complex" if it has more than 2
+      // operands. We will promote a SExt used in such complex GEP as we
+      // expect some computation to be merged if they are done on 64 bits.
+      if (GEPInst->getNumOperands() > 2) {
+        AllowPromotionWithoutCommonHeader = true;
+        break;
+      }
+    }
+  }
+  return Considerable;
+}
+
 unsigned AArch64TTIImpl::getCacheLineSize() {
   return ST->getCacheLineSize();
 }
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
index a7f7fb9457a..db017258c83 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
@@ -121,6 +121,10 @@ public:
                                  ArrayRef<unsigned> Indices, unsigned Alignment,
                                  unsigned AddressSpace);
 
+  bool
+  shouldConsiderAddressTypePromotion(const Instruction &I,
+                                     bool &AllowPromotionWithoutCommonHeader);
+
   unsigned getCacheLineSize();
 
   unsigned getPrefetchDistance();