diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index a3eab28..a2a9941 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -87,6 +87,22 @@ jobs:
                 echo "EM_CONFIG=$EM_CONFIG" >> $GITHUB_ENV
                 echo "$EMSDK:$EMSDK/upstream/emscripten" >> $GITHUB_PATH
 
+            - name: Cache emscripten build products
+              id: cache-emscripten
+              uses: actions/cache@v5
+              env:
+                cache-name: emscripten-cache
+              with:
+                path: ${{ env.EMSDK }}/upstream/emscripten/cache
+                key: ${{ runner.os }}-${{ env.cache-name }}-${{ inputs.emsdk_version }}
+
+            - if: ${{ steps.cache-emscripten.outputs.cache-hit }} == 'true'
+              name: Run emscripten sanity check after restoring cache
+              run: |
+                source "$EMSDK/emsdk_env.sh"
+                emcc --check
+                exit $?
+
             - name: Build TS App
               run: |
                 source "$EMSDK/emsdk_env.sh"
diff --git a/Makefile b/Makefile
index b3eb956..a28ec93 100644
--- a/Makefile
+++ b/Makefile
@@ -47,8 +47,9 @@ opus-wasmlib: $(LIBOPUS_WASM_LIB)
 
 # common EMCC options
 define EMCC_OPTS
--O2 \
+-O3 \
 -msimd128 \
+-flto \
 --minify 0 \
 -gsource-map \
 -s WASM=1 \
@@ -109,9 +110,11 @@ $(LIBOPUS_WASM_LIB): $(LIBOPUS_BUILD)/Makefile
 
 libopus-configure: $(LIBOPUS_BUILD)/Makefile
 
- $(LIBOPUS_BUILD)/Makefile: $(LIBOPUS_SRC)/configure
+$(LIBOPUS_BUILD)/Makefile: $(LIBOPUS_SRC)/configure
 	mkdir -p $(LIBOPUS_BUILD)
-	cd $(LIBOPUS_BUILD); CFLAGS="-O3 -msimd128" emconfigure $(CURDIR)/$(LIBOPUS_SRC)/configure \
+	cd $(LIBOPUS_BUILD); \
+	  CFLAGS="-O3 -msimd128 -flto" \
+	  emconfigure $(CURDIR)/$(LIBOPUS_SRC)/configure \
 	  --host=wasm32-unknown-emscripten \
 	  --enable-float-approx \
 	  --disable-rtcd \