Add a CI step with simd disabled

Author: byroot

.github/workflows/ci.yml

@@ -14,26 +14,28 @@ jobs:
 
   host:
     needs: ruby-versions
-    name: ${{ matrix.os }} ${{ matrix.ruby }}
+    name: ${{ matrix.os }} ${{ matrix.ruby }} ${{ matrix.env }}
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os:
-        - ubuntu-latest
-        - macos-14
-        - windows-latest
+          - ubuntu-latest
+          - macos-14
+          - windows-latest
         ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
+        env: ~
         include:
-        - { os: ubuntu-24.04-arm, ruby: 3.4 }
-        - { os: macos-13, ruby: 3.4 }
-        - { os: windows-latest , ruby: mswin     } # ruby/ruby windows CI
-        - { os: ubuntu-latest  , ruby: jruby-9.4 } # Ruby 3.1
-        - { os: macos-latest   , ruby: truffleruby-head }
-        - { os: ubuntu-latest  , ruby: truffleruby-head }
+          - { os: ubuntu-24.04-arm, ruby: 3.4 }
+          - { os: ubuntu-latest  , ruby: 3.4, env: "JSON_DISABLE_SIMD=1" }
+          - { os: macos-13, ruby: 3.4 }
+          - { os: windows-latest , ruby: mswin     } # ruby/ruby windows CI
+          - { os: ubuntu-latest  , ruby: jruby-9.4 } # Ruby 3.1
+          - { os: macos-latest   , ruby: truffleruby-head }
+          - { os: ubuntu-latest  , ruby: truffleruby-head }
         exclude:
-        - { os: windows-latest, ruby: jruby }
-        - { os: windows-latest, ruby: jruby-head }
+          - { os: windows-latest, ruby: jruby }
+          - { os: windows-latest, ruby: jruby-head }
 
     steps:
       - uses: actions/checkout@v4
@@ -49,9 +51,9 @@ jobs:
           bundle config --without benchmark
           bundle install
 
-      - run: rake compile
+      - run: rake compile ${{ matrix.env }}
 
-      - run: rake test JSON_COMPACT=1
+      - run: rake test JSON_COMPACT=1 ${{ matrix.env }}
 
       - run: rake build
 

ext/json/ext/generator/extconf.rb

@@ -7,7 +7,7 @@
   append_cflags("-std=c99")
   $defs << "-DJSON_GENERATOR"
 
-  if enable_config('generator-use-simd', default=true)
+  if enable_config('generator-use-simd', default=!ENV["JSON_DISABLE_SIMD"])
     if RbConfig::CONFIG['host_cpu'] =~ /^(arm.*|aarch64.*)/
       # Try to compile a small program using NEON instructions
       if have_header('arm_neon.h')
@@ -31,7 +31,7 @@
       SRC
         $defs.push("-DENABLE_SIMD")
     end
-    
+
     have_header('cpuid.h')
   end