diff --git a/flang/include/flang/Tools/CLOptions.inc b/flang/include/flang/Tools/CLOptions.inc
--- a/flang/include/flang/Tools/CLOptions.inc
+++ b/flang/include/flang/Tools/CLOptions.inc
@@ -154,10 +154,12 @@
   // simplify the IR
   mlir::GreedyRewriteConfig config;
   config.enableRegionSimplification = false;
+  pm.addPass(mlir::createCSEPass());
   fir::addAVC(pm);
   pm.addNestedPass<mlir::func::FuncOp>(fir::createCharacterConversionPass());
   pm.addPass(mlir::createCanonicalizerPass(config));
   pm.addPass(fir::createSimplifyRegionLitePass());
+  pm.addPass(mlir::createCSEPass());
   fir::addMemoryAllocationOpt(pm);
 
   // The default inliner pass adds the canonicalizer pass with the default
@@ -173,6 +175,7 @@
 
   pm.addPass(mlir::createCanonicalizerPass(config));
   pm.addPass(fir::createSimplifyRegionLitePass());
+  pm.addPass(mlir::createCSEPass());
 }
 
 #if !defined(FLANG_EXCLUDE_CODEGEN)
diff --git a/flang/test/Driver/mlir-pass-pipeline.f90 b/flang/test/Driver/mlir-pass-pipeline.f90
--- a/flang/test/Driver/mlir-pass-pipeline.f90
+++ b/flang/test/Driver/mlir-pass-pipeline.f90
@@ -5,11 +5,13 @@
 
 ! CHECK: Pass statistics report
 
+! CHECK: CSE
 ! CHECK-LABEL: 'func.func' Pipeline
 ! CHECK: ArrayValueCopy
 ! CHECK: CharacterConversion
 ! CHECK: Canonicalizer
 ! CHECK: SimplifyRegionLite
+! CHECK: CSE
 
 ! CHECK-LABEL: 'func.func' Pipeline
 ! CHECK: MemoryAllocationOpt
@@ -21,6 +23,7 @@
 ! CHECK: SCFToControlFlow
 ! CHECK: Canonicalizer
 ! CHECK: SimplifyRegionLite
+! CHECK: CSE
 ! CHECK: BoxedProcedurePass
 
 ! CHECK-LABEL: 'func.func' Pipeline
diff --git a/flang/test/Fir/basic-program.fir b/flang/test/Fir/basic-program.fir
--- a/flang/test/Fir/basic-program.fir
+++ b/flang/test/Fir/basic-program.fir
@@ -14,11 +14,13 @@
 
 // PASSES: Pass statistics report
 
+// PASSES: CSE
 // PASSES-LABEL: 'func.func' Pipeline
 // PASSES: ArrayValueCopy
 // PASSES: CharacterConversion
 // PASSES: Canonicalizer
 // PASSES: SimplifyRegionLite
+// PASSES: CSE
 
 // PASSES-LABEL: 'func.func' Pipeline
 // PASSES: MemoryAllocationOpt
@@ -30,6 +32,7 @@
 // PASSES: SCFToControlFlow
 // PASSES: Canonicalizer
 // PASSES: SimplifyRegionLite
+// PASSES: CSE
 // PASSES: BoxedProcedurePass
 
 // PASSES-LABEL: 'func.func' Pipeline