diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 5847878d389..ff92da55950 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -98,6 +98,7 @@ jobs:
           --compiler $CXX
           --c-compiler $CC
           --mode ${{ matrix.mode }}
+          --cflags "-march=haswell"
           ${{ matrix.cooks }}
           ${{ matrix.enables }} ;