make it build in Debug

numerics/fma.hpp

@@ -19,31 +19,34 @@ constexpr bool CanEmitFMAInstructions = true;
 constexpr bool CanEmitFMAInstructions = false;
 #endif
 
-// The functions in this file unconditionally wrap the appropriate intrinsics.
-// The caller may only use them if |UseHardwareFMA| is true.
 #if PRINCIPIA_USE_FMA_IF_AVAILABLE()
+#define PRINCIPIA_USE_HARDWARE_FMA_DEFAULT \
+  (CanEmitFMAInstructions && HasCPUFeatures(CPUFeatureFlags::FMA));
+#else
+#define PRINCIPIA_USE_HARDWARE_FMA_DEFAULT false;
+#endif
+
 #if PRINCIPIA_CAN_OVERRIDE_FMA_USAGE_AT_RUNTIME
-inline bool DefaultUseHardwareFMA =
-    CanEmitFMAInstructions && HasCPUFeatures(CPUFeatureFlags::FMA);
-inline bool InternalUseHardwareFMA = DefaultUseHardwareFMA;
+inline bool InternalUseHardwareFMA = PRINCIPIA_USE_HARDWARE_FMA_DEFAULT;
 class FMAPreventer {
  public:
   FMAPreventer() {
     InternalUseHardwareFMA = false;
   }
   ~FMAPreventer() {
-    InternalUseHardwareFMA = DefaultUseHardwareFMA;
+    InternalUseHardwareFMA = PRINCIPIA_USE_HARDWARE_FMA_DEFAULT;
   }
 };
 inline bool const& UseHardwareFMA = InternalUseHardwareFMA;
 #else
-inline bool const UseHardwareFMA =
-    CanEmitFMAInstructions && HasCPUFeatures(CPUFeatureFlags::FMA);
+inline bool const UseHardwareFMA = PRINCIPIA_USE_HARDWARE_FMA_DEFAULT;
 class FMAPreventer;  // Undefined.
 #endif
-#else
-inline bool const UseHardwareFMA = false;
-#endif
+
+#undef PRINCIPIA_USE_HARDWARE_FMA_DEFAULT
+
+// The functions in this file unconditionally wrap the appropriate intrinsics.
+// The caller may only use them if |UseHardwareFMA| is true.
 
 // ⟦ab + c⟧.
 inline double FusedMultiplyAdd(double a, double b, double c);