diff --git a/.github/actions/build-upstream/action.yml b/.github/actions/build-upstream/action.yml
index 81a6c65a6c..5f64304ad0 100644
--- a/.github/actions/build-upstream/action.yml
+++ b/.github/actions/build-upstream/action.yml
@@ -184,7 +184,10 @@ runs:
     - name: Build trampoline shim binary (Windows only)
       if: steps.native.outputs.build == 'true' && contains(inputs.target, 'windows')
       shell: bash
-      run: node packages/tools/src/build-trampoline.ts --release --target "${INPUTS_TARGET}"
+      # The standalone trampoline keeps its own size-optimized Cargo profile.
+      run: |
+        env -u CARGO_PROFILE_RELEASE_LTO -u CARGO_PROFILE_RELEASE_CODEGEN_UNITS \
+          node packages/tools/src/build-trampoline.ts --release --target "${INPUTS_TARGET}"
       env:
         INPUTS_TARGET: ${{ inputs.target }}
 
diff --git a/.github/actions/build-windows-cli/action.yml b/.github/actions/build-windows-cli/action.yml
index 5689767dbf..dc97f1dd12 100644
--- a/.github/actions/build-windows-cli/action.yml
+++ b/.github/actions/build-windows-cli/action.yml
@@ -91,7 +91,10 @@ runs:
     - name: Build trampoline shim binary
       if: steps.binaries-cache.outputs.cache-hit != 'true'
       shell: bash
-      run: node packages/tools/src/build-trampoline.ts --xwin --release --target x86_64-pc-windows-msvc
+      # The standalone trampoline keeps its own size-optimized Cargo profile.
+      run: |
+        env -u CARGO_PROFILE_RELEASE_LTO -u CARGO_PROFILE_RELEASE_CODEGEN_UNITS \
+          node packages/tools/src/build-trampoline.ts --xwin --release --target x86_64-pc-windows-msvc
       env:
         XWIN_ACCEPT_LICENSE: '1'
 
diff --git a/.github/actions/compute-native-cache-input-hash/action.yml b/.github/actions/compute-native-cache-input-hash/action.yml
index e0e0ba9a62..530b413bed 100644
--- a/.github/actions/compute-native-cache-input-hash/action.yml
+++ b/.github/actions/compute-native-cache-input-hash/action.yml
@@ -13,7 +13,9 @@ runs:
       id: compute
       shell: bash
       run: |
-        echo "hash=$NATIVE_CACHE_INPUT_HASH" >> "$GITHUB_OUTPUT"
+        # Test builds and published builds must never share native binaries.
+        profile="${CARGO_PROFILE_RELEASE_LTO:-manifest}-${CARGO_PROFILE_RELEASE_CODEGEN_UNITS:-manifest}"
+        echo "hash=${NATIVE_CACHE_INPUT_HASH}-${profile}" >> "$GITHUB_OUTPUT"
       env:
         # crates/vp_cli_snapshots is excluded: the snapshot suite (runner,
         # vpt, fixtures, recorded .md baselines) never feeds the native
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d46a9fe600..4172b466fa 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -65,6 +65,10 @@ jobs:
     permissions:
       contents: read
       packages: read
+    # Test native code without whole-program optimization.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
       - uses: ./.github/actions/clone
@@ -373,6 +377,10 @@ jobs:
     if: needs.detect-changes.outputs.code-changed == 'true'
     name: Build Windows CLI binaries
     runs-on: namespace-profile-linux-x64-default
+    # Test native code without whole-program optimization.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
       - uses: ./.github/actions/clone
@@ -946,6 +954,10 @@ jobs:
           - os: namespace-profile-mac-default
             target: aarch64-apple-darwin
     runs-on: ${{ matrix.os }}
+    # Test native code without whole-program optimization.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
       - uses: ./.github/actions/clone
@@ -1301,6 +1313,10 @@ jobs:
     needs:
       - download-previous-rolldown-binaries
     runs-on: namespace-profile-linux-x64-default
+    # Test native code without whole-program optimization.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
       - uses: ./.github/actions/clone
diff --git a/.github/workflows/e2e-test.yml b/.github/workflows/e2e-test.yml
index 2c1465fed1..acf8584a10 100644
--- a/.github/workflows/e2e-test.yml
+++ b/.github/workflows/e2e-test.yml
@@ -80,6 +80,10 @@ jobs:
     permissions:
       contents: read
       packages: read
+    # Test native code without whole-program optimization.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
       - uses: ./.github/actions/clone
diff --git a/.github/workflows/reusable-ecosystem-ci.yml b/.github/workflows/reusable-ecosystem-ci.yml
index 097aa76cc6..15b527cdbe 100644
--- a/.github/workflows/reusable-ecosystem-ci.yml
+++ b/.github/workflows/reusable-ecosystem-ci.yml
@@ -29,6 +29,10 @@ jobs:
     permissions:
       contents: read
       packages: read
+    # Test native code without whole-program optimization.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
       - uses: ./.github/actions/clone
diff --git a/.github/workflows/test-vp-create.yml b/.github/workflows/test-vp-create.yml
index 1e4dc124cf..3dc776367d 100644
--- a/.github/workflows/test-vp-create.yml
+++ b/.github/workflows/test-vp-create.yml
@@ -65,6 +65,10 @@ jobs:
   build:
     name: Build vite-plus packages
     runs-on: namespace-profile-linux-x64-default
+    # Match the CLI build profile to reuse its native and Cargo caches.
+    env:
+      CARGO_PROFILE_RELEASE_LTO: 'off'
+      CARGO_PROFILE_RELEASE_CODEGEN_UNITS: '16'
     permissions:
       contents: read
       packages: read