3 files changed, 26 insertions, 1 deletions
diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
index ecd003c..098bcfa 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -9559,3 +9559,20 @@ bool LoongArchTargetLowering::shouldScalarizeBinop(SDValue VecOp) const {
   EVT ScalarVT = VecVT.getScalarType();
   return isOperationLegalOrCustomOrPromote(Opc, ScalarVT);
 }
+
+bool LoongArchTargetLowering::isExtractSubvectorCheap(EVT ResVT, EVT SrcVT,
+                                                      unsigned Index) const {
+  if (!isOperationLegalOrCustom(ISD::EXTRACT_SUBVECTOR, ResVT))
+    return false;
+
+  // Extract a 128-bit subvector from index 0 of a 256-bit vector is free.
+  return Index == 0;
+}
+
+bool LoongArchTargetLowering::isExtractVecEltCheap(EVT VT,
+                                                   unsigned Index) const {
+  EVT EltVT = VT.getScalarType();
+
+  // Extract a scalar FP value from index 0 of a vector is free.
+  return (EltVT == MVT::f32 || EltVT == MVT::f64) && Index == 0;
+}
diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
index 3c00296..9b60a9f 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.h
@@ -338,6 +338,9 @@ public:
                                          unsigned Depth) const override;
 
   bool shouldScalarizeBinop(SDValue VecOp) const override;
+  bool isExtractSubvectorCheap(EVT ResVT, EVT SrcVT,
+                               unsigned Index) const override;
+  bool isExtractVecEltCheap(EVT VT, unsigned Index) const override;
 
   /// Check if a constant splat can be generated using [x]vldi, where imm[12]
   /// is 1.
diff --git a/llvm/lib/Target/LoongArch/LoongArchTargetMachine.cpp b/llvm/lib/Target/LoongArch/LoongArchTargetMachine.cpp
index d0a8aba..c5e26c1 100644
--- a/llvm/lib/Target/LoongArch/LoongArchTargetMachine.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchTargetMachine.cpp
@@ -57,6 +57,11 @@ static cl::opt<bool>
                            cl::desc("Enable the loop data prefetch pass"),
                            cl::init(false));
 
+static cl::opt<bool>
+    EnableMergeBaseOffset("loongarch-enable-merge-offset",
+                          cl::desc("Enable the merge base offset pass"),
+                          cl::init(true), cl::Hidden);
+
 static Reloc::Model getEffectiveRelocModel(const Triple &TT,
                                            std::optional<Reloc::Model> RM) {
   return RM.value_or(Reloc::Static);
@@ -214,7 +219,7 @@ void LoongArchPassConfig::addMachineSSAOptimization() {
 
 void LoongArchPassConfig::addPreRegAlloc() {
   addPass(createLoongArchPreRAExpandPseudoPass());
-  if (TM->getOptLevel() != CodeGenOptLevel::None)
+  if (TM->getOptLevel() != CodeGenOptLevel::None && EnableMergeBaseOffset)
     addPass(createLoongArchMergeBaseOffsetOptPass());
 }