diff --git a/WORKSPACE b/WORKSPACE
index 1d908e8..bdaf84b 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -15,9 +15,9 @@
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
-LLVM_COMMIT = "91e7a17133324ac4beaf6ed45c170436c2d91c98"
+LLVM_COMMIT = "d1978fa4bf0d7da0b3cd88879e9411467edcb01f"
 
-LLVM_SHA256 = "07ef834c47337dc7b38c765693a3b5a1835aac2f716fd9a06c374a71722c20de"
+LLVM_SHA256 = "7cf83492b954d713f727bbafb00aa93e412281cc6e0cab90a38a3c00ca63cc4a"
 
 LLVM_BAZEL_TAG = "llvm-project-{commit}".format(commit = LLVM_COMMIT)
 
diff --git a/build_tools/llvm_version.txt b/build_tools/llvm_version.txt
index 8e58c2d..e746541 100644
--- a/build_tools/llvm_version.txt
+++ b/build_tools/llvm_version.txt
@@ -1,2 +1,2 @@
-91e7a17133324ac4beaf6ed45c170436c2d91c98
+d1978fa4bf0d7da0b3cd88879e9411467edcb01f
 
diff --git a/lib/Dialect/mhlo/transforms/legalize_gather_to_torch_index_select.cc b/lib/Dialect/mhlo/transforms/legalize_gather_to_torch_index_select.cc
index ebaef67..0f6efbc 100644
--- a/lib/Dialect/mhlo/transforms/legalize_gather_to_torch_index_select.cc
+++ b/lib/Dialect/mhlo/transforms/legalize_gather_to_torch_index_select.cc
@@ -133,7 +133,7 @@ struct LegalizeGatherToTorchIndexSelectPass
   void runOnFunction() override {
     OwningRewritePatternList patterns;
     PopulateGatherToTorchIndexSelectPatterns(&getContext(), &patterns);
-    applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
   }
 };
 }  // namespace
diff --git a/lib/Dialect/mhlo/transforms/legalize_to_standard.cc b/lib/Dialect/mhlo/transforms/legalize_to_standard.cc
index 454ec18..986589a 100644
--- a/lib/Dialect/mhlo/transforms/legalize_to_standard.cc
+++ b/lib/Dialect/mhlo/transforms/legalize_to_standard.cc
@@ -201,7 +201,7 @@ void PopulateMhloToStdPatterns(OwningRewritePatternList *patterns,
 void LegalizeToStandardPass::runOnFunction() {
   OwningRewritePatternList patterns;
   mlir::mhlo::PopulateMhloToStdPatterns(&patterns, &getContext());
-  applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+  (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
 }
 
 }  // end namespace mhlo
diff --git a/lib/Dialect/mhlo/transforms/legalize_trigonometric_to_approximation.cc b/lib/Dialect/mhlo/transforms/legalize_trigonometric_to_approximation.cc
index a883209..4a73f1b 100644
--- a/lib/Dialect/mhlo/transforms/legalize_trigonometric_to_approximation.cc
+++ b/lib/Dialect/mhlo/transforms/legalize_trigonometric_to_approximation.cc
@@ -259,7 +259,7 @@ struct LegalizeTrigonometricToApproximationPass
   void runOnFunction() override {
     OwningRewritePatternList patterns;
     PopulateTrigonometricToApproximationPatterns(&getContext(), &patterns);
-    applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
   }
 };
 
diff --git a/lib/Dialect/mhlo/transforms/lhlo_fuse_linalg.cc b/lib/Dialect/mhlo/transforms/lhlo_fuse_linalg.cc
index a421d63..7acaf4a 100644
--- a/lib/Dialect/mhlo/transforms/lhlo_fuse_linalg.cc
+++ b/lib/Dialect/mhlo/transforms/lhlo_fuse_linalg.cc
@@ -164,7 +164,7 @@ class LhloFuseLinalgPass
       }
     });
     auto patterns = linalg::getLinalgTilingCanonicalizationPatterns(ctx);
-    applyPatternsAndFoldGreedily(func, std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(func, std::move(patterns));
 
     // Fuse producers of tiled linalg ops.
     llvm::SmallDenseSet<Operation*> erase_set;
@@ -185,7 +185,7 @@ class LhloFuseLinalgPass
       }
 
       auto patterns = linalg::getLinalgTilingCanonicalizationPatterns(ctx);
-      applyPatternsAndFoldGreedily(func, std::move(patterns));
+      (void)applyPatternsAndFoldGreedily(func, std::move(patterns));
     }
     for (auto* e : erase_set) e->erase();
   }
diff --git a/lib/Dialect/mhlo/transforms/lhlo_legalize_to_affine.cc b/lib/Dialect/mhlo/transforms/lhlo_legalize_to_affine.cc
index 72fd422..72af982 100644
--- a/lib/Dialect/mhlo/transforms/lhlo_legalize_to_affine.cc
+++ b/lib/Dialect/mhlo/transforms/lhlo_legalize_to_affine.cc
@@ -158,7 +158,7 @@ struct LhloLegalizeToAffinePass
     OwningRewritePatternList patterns;
     auto func = getFunction();
     populateLHLOToAffineConversionPattern(func.getContext(), &patterns);
-    applyPatternsAndFoldGreedily(func, std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(func, std::move(patterns));
   }
 };
 
diff --git a/lib/Dialect/mhlo/transforms/lower_complex.cc b/lib/Dialect/mhlo/transforms/lower_complex.cc
index 7bea88f..c2c3628 100644
--- a/lib/Dialect/mhlo/transforms/lower_complex.cc
+++ b/lib/Dialect/mhlo/transforms/lower_complex.cc
@@ -70,7 +70,7 @@ void LowerComplexPass::runOnFunction() {
   OwningRewritePatternList patterns;
   mlir::mhlo::PopulateComplexLoweringPatterns(&getContext(), &patterns);
 
-  applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+  (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
 }
 
 std::unique_ptr<FunctionPass> mlir::mhlo::createLowerComplexPass() {
diff --git a/lib/Dialect/mhlo/transforms/lower_general_dot.cc b/lib/Dialect/mhlo/transforms/lower_general_dot.cc
index ea8783f..57885f4 100644
--- a/lib/Dialect/mhlo/transforms/lower_general_dot.cc
+++ b/lib/Dialect/mhlo/transforms/lower_general_dot.cc
@@ -182,7 +182,7 @@ struct LegalizeGeneralDotPass
   void runOnFunction() override {
     OwningRewritePatternList patterns;
     mlir::mhlo::PopulateGeneralDotOpLoweringPatterns(&patterns, &getContext());
-    applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
   }
 };
 
diff --git a/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc b/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc
index 62fde5e..0d181e4 100644
--- a/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc
+++ b/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc
@@ -42,7 +42,7 @@ void OptimizeMhloPass::runOnFunction() {
   mlir::OwningRewritePatternList patterns;
   mlir::mhlo::PopulateOptimizeMHLOPatterns(&getContext(), &patterns);
 
-  applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+  (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
 }
 
 std::unique_ptr<mlir::FunctionPass> mlir::mhlo::createOptimizeMhloPass() {
diff --git a/lib/Dialect/mhlo/transforms/test_infer_shaped_type_pass.cc b/lib/Dialect/mhlo/transforms/test_infer_shaped_type_pass.cc
index fed7f70..9cf7c00 100644
--- a/lib/Dialect/mhlo/transforms/test_infer_shaped_type_pass.cc
+++ b/lib/Dialect/mhlo/transforms/test_infer_shaped_type_pass.cc
@@ -87,7 +87,7 @@ struct TestInferShapedTypeMethodsPass
     OwningRewritePatternList patterns;
     patterns.insert<ReifyReturnTypeShapesPattern>(&getContext());
     patterns.insert<InferReturnTypeComponentsPattern>(&getContext());
-    applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(getFunction(), std::move(patterns));
   }
 };
 
diff --git a/lib/Dialect/mhlo/transforms/unfuse_batch_norm_pass.cc b/lib/Dialect/mhlo/transforms/unfuse_batch_norm_pass.cc
index 19261d4..e2b684a 100644
--- a/lib/Dialect/mhlo/transforms/unfuse_batch_norm_pass.cc
+++ b/lib/Dialect/mhlo/transforms/unfuse_batch_norm_pass.cc
@@ -32,7 +32,7 @@ struct TestUnfuseBatchNormPass
   void runOnOperation() override {
     OwningRewritePatternList patterns;
     PopulateUnfuseBatchNormPatterns(&getContext(), &patterns);
-    applyPatternsAndFoldGreedily(getOperation(), std::move(patterns));
+    (void)applyPatternsAndFoldGreedily(getOperation(), std::move(patterns));
   }
 };