diff --git a/.github/workflows/test-linux.yml b/.github/workflows/test-linux.yml
index 9aa952e45..d601aa966 100644
--- a/.github/workflows/test-linux.yml
+++ b/.github/workflows/test-linux.yml
@@ -120,6 +120,7 @@ jobs:
           make -j${{ env.procs }} CCXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC
 
       - name: Run tests
+        if: (matrix.cpp_std == 'c++11') && (matrix.compiler == 'gcc-11')
         shell: bash
         run: |
           make -j${{ env.procs }} test CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC
diff --git a/.github/workflows/test-macos.yml b/.github/workflows/test-macos.yml
index 09ab382bf..b14ce8633 100644
--- a/.github/workflows/test-macos.yml
+++ b/.github/workflows/test-macos.yml
@@ -67,6 +67,7 @@ jobs:
           make -j${{ env.procs }} CXXSTD=${{ matrix.cpp_std }} CC=cc CXX=cc LD=cc
 
       - name: Run tests
+        if: matrix.cpp_std == 'c++11'
         shell: bash
         run: |
           make -j${{ env.procs }} test CXXSTD=${{ matrix.cpp_std }} CC=cc CXX=cc LD=cc
@@ -119,36 +120,8 @@ jobs:
       - name: Checkout Yosys
         uses: actions/checkout@v2
 
-      - name: Get iverilog
-        shell: bash
-        run: |
-          git clone https://github.com/steveicarus/iverilog.git
-
-      - name: Cache iverilog
-        id: cache-iverilog-homebrew
-        uses: actions/cache@v2
-        with:
-          path: .local/
-          key: ${{ matrix.os.id }}-homebrew-${{ hashFiles('iverilog/.git/refs/heads/master') }}
-
-      - name: Build iverilog
-        if: steps.cache-iverilog.outputs.cache-hit != 'true'
-        shell: bash
-        run: |
-          mkdir -p $GITHUB_WORKSPACE/.local
-          cd iverilog
-          autoconf
-          CC=gcc CXX=g++ ./configure --prefix=$GITHUB_WORKSPACE/.local
-          make -j${{ env.procs }}
-          make install
-
       - name: Build yosys
         shell: bash
         run: |
           make config-gcc
           make -j${{ env.procs }} CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC
-
-      - name: Run tests
-        shell: bash
-        run: |
-          make -j${{ env.procs }} test CXXSTD=${{ matrix.cpp_std }} CC=$CC CXX=$CC LD=$CC