Add a different implementation of Differentiation

CMakeLists.txt

@@ -402,6 +402,10 @@ option(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING
   "Enable experimental Swift differentiable programming features"
   FALSE)
 
+option(SWIFT_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING_FUTURE_IMPLEMENTATION
+  "Build Differentation as it would be long term (i.e. no tgmath)"
+  FALSE)
+
 option(SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY
   "Enable experimental Swift concurrency model"
   FALSE)
@@ -856,6 +860,9 @@ if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_SDK_OVERLAY)
   message(STATUS "")
 
   message(STATUS "Differentiable Programming Support: ${SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING}")
+  if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
+    message(STATUS "  Building future implementation for Differentiable Programming: ${SWIFT_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING_FUTURE_IMPLEMENTATION}")
+  endif()
   message(STATUS "Concurrency Support: ${SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY}")
   message(STATUS "")
 else()

stdlib/public/Differentiation/CMakeLists.txt

@@ -10,33 +10,56 @@
 #
 #===----------------------------------------------------------------------===#
 
-add_swift_target_library(swift_Differentiation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
-  Differentiable.swift
-  DifferentialOperators.swift
-  DifferentiationUtilities.swift
-  AnyDifferentiable.swift
-  ArrayDifferentiation.swift
-  OptionalDifferentiation.swift
+if(NOT SWIFT_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING_FUTURE_IMPLEMENTATION)
+  add_swift_target_library(swift_Differentiation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
+    Differentiable.swift
+    DifferentialOperators.swift
+    DifferentiationUtilities.swift
+    AnyDifferentiable.swift
+    ArrayDifferentiation.swift
+    OptionalDifferentiation.swift
 
-  GYB_SOURCES
-    FloatingPointDifferentiation.swift.gyb
-    TgmathDerivatives.swift.gyb
-    SIMDDifferentiation.swift.gyb
+    GYB_SOURCES
+      FloatingPointDifferentiation.swift.gyb
+      TgmathDerivatives.swift.gyb
+      SIMDDifferentiation.swift.gyb
 
-  SWIFT_MODULE_DEPENDS_OSX Darwin
-  SWIFT_MODULE_DEPENDS_IOS Darwin
-  SWIFT_MODULE_DEPENDS_TVOS Darwin
-  SWIFT_MODULE_DEPENDS_WATCHOS Darwin
-  SWIFT_MODULE_DEPENDS_LINUX Glibc
-  SWIFT_MODULE_DEPENDS_FREEBSD Glibc
-  SWIFT_MODULE_DEPENDS_OPENBSD Glibc
-  SWIFT_MODULE_DEPENDS_CYGWIN Glibc
-  SWIFT_MODULE_DEPENDS_HAIKU Glibc
-  SWIFT_MODULE_DEPENDS_WINDOWS MSVCRT
+    SWIFT_MODULE_DEPENDS_OSX Darwin
+    SWIFT_MODULE_DEPENDS_IOS Darwin
+    SWIFT_MODULE_DEPENDS_TVOS Darwin
+    SWIFT_MODULE_DEPENDS_WATCHOS Darwin
+    SWIFT_MODULE_DEPENDS_LINUX Glibc
+    SWIFT_MODULE_DEPENDS_FREEBSD Glibc
+    SWIFT_MODULE_DEPENDS_OPENBSD Glibc
+    SWIFT_MODULE_DEPENDS_CYGWIN Glibc
+    SWIFT_MODULE_DEPENDS_HAIKU Glibc
+    SWIFT_MODULE_DEPENDS_WINDOWS MSVCRT
 
-  SWIFT_COMPILE_FLAGS
-    ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
-    -parse-stdlib
-  LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
-  DARWIN_INSTALL_NAME_DIR "@rpath"
-  INSTALL_IN_COMPONENT stdlib)
+    SWIFT_COMPILE_FLAGS
+      ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+      -parse-stdlib
+    LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
+    DARWIN_INSTALL_NAME_DIR "@rpath"
+    INSTALL_IN_COMPONENT stdlib)
+else()
+  # This implementation will quickly evolve, so it does not make sense
+  # to share code with the other implementation
+  add_swift_target_library(swift_Differentiation ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
+    Differentiable.swift
+    DifferentialOperators.swift
+    DifferentiationUtilities.swift
+    AnyDifferentiable.swift
+    ArrayDifferentiation.swift
+    OptionalDifferentiation.swift
+
+    GYB_SOURCES
+      FloatingPointDifferentiation.swift.gyb
+      SIMDDifferentiation.swift.gyb
+
+    SWIFT_COMPILE_FLAGS
+      ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+      -parse-stdlib
+    LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
+    DARWIN_INSTALL_NAME_DIR "@rpath"
+    INSTALL_IN_COMPONENT stdlib)
+endif()