diff --git a/gfx/layers/moz.build b/gfx/layers/moz.build
index ed9fb8f0cada..b81f0de7f694 100755
--- a/gfx/layers/moz.build
+++ b/gfx/layers/moz.build
@@ -422,11 +422,13 @@ UNIFIED_SOURCES += [
     'ipc/UiCompositorControllerParent.cpp',
     'ipc/VideoBridgeChild.cpp',
     'ipc/VideoBridgeParent.cpp',
+    'Layers.cpp',
     'LayerScope.cpp',
     'LayersHelpers.cpp',
     'LayersLogging.cpp',
     'LayerSorter.cpp',
     'LayersTypes.cpp',
+    'LayerTreeInvalidation.cpp',
     'mlgpu/BufferCache.cpp',
     'mlgpu/CanvasLayerMLGPU.cpp',
     'mlgpu/ContainerLayerMLGPU.cpp',
@@ -480,8 +482,6 @@ UNIFIED_SOURCES += [
 SOURCES += [
     'basic/BasicImageLayer.cpp',
     'ImageContainer.cpp',
-    'Layers.cpp',
-    'LayerTreeInvalidation.cpp',
     'PersistentBufferProvider.cpp',
     'protobuf/LayerScopePacket.pb.cc',
     'wr/WebRenderTextureHost.cpp',
@@ -490,14 +490,6 @@ SOURCES += [
 DEFINES['GOOGLE_PROTOBUF_NO_RTTI'] = True
 DEFINES['GOOGLE_PROTOBUF_NO_STATIC_INITIALIZER'] = True
 
-# Workaround compiler bug (Bug 795594)
-if CONFIG['CC_TYPE'] in ('msvc', 'clang-cl') and CONFIG['CPU_ARCH'] == 'x86_64':
-    for src in [
-        'Layers.cpp',
-        'LayerTreeInvalidation.cpp',
-    ]:
-        SOURCES[src].no_pgo = True
-
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
     SOURCES += [
         'basic/MacIOSurfaceTextureHostBasic.cpp',
diff --git a/js/src/moz.build b/js/src/moz.build
index 9195cdb086de..bfe211d72195 100755
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -414,8 +414,8 @@ UNIFIED_SOURCES += [
 
 # builtin/Array.cpp and vm/JSAtom.cpp cannot be built in unified mode because
 #   xpcshell is broken during packaging when compiled with gcc-4.8.2
-# builtin/RegExp.cpp cannot be built in unified mode because it is built
-#   without PGO
+# builtin/RegExp.cpp cannot be built in unified mode because it causes huge
+#   win32 test slowdowns
 # frontend/Parser.cpp cannot be built in unified mode because of explicit
 #   template instantiations.
 # jsmath.cpp cannot be built in unified mode because it needs to re-#define the
@@ -724,10 +724,6 @@ if CONFIG['MOZ_LINKER']:
     DEFINES['MOZ_LINKER'] = True
 
 if CONFIG['CC_TYPE'] in ('msvc', 'clang-cl'):
-    if CONFIG['CPU_ARCH'] == 'x86':
-        SOURCES['builtin/RegExp.cpp'].no_pgo = True # Bug 772303
-    elif CONFIG['CPU_ARCH'] == 'x86_64' and CONFIG['JS_HAS_CTYPES']:
-        SOURCES['ctypes/CTypes.cpp'].no_pgo = True # Bug 810661
     # Prevent floating point errors caused by VC++ optimizations
     # XXX We should add this to CXXFLAGS, too?
     CFLAGS += ['-fp:precise']
diff --git a/netwerk/sctp/datachannel/moz.build b/netwerk/sctp/datachannel/moz.build
index 52cf72908545..8a5735a1b419 100644
--- a/netwerk/sctp/datachannel/moz.build
+++ b/netwerk/sctp/datachannel/moz.build
@@ -30,7 +30,5 @@ if CONFIG['OS_TARGET'] == 'WINNT':
 else:
     DEFINES['__Userspace_os_%s' % CONFIG['OS_TARGET']] = 1
 
-NO_PGO = True # Don't PGO
-
 if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
     CXXFLAGS += ['-Wno-error=shadow']
diff --git a/netwerk/sctp/src/moz.build b/netwerk/sctp/src/moz.build
index dd2af17ba81a..6564496e40e0 100644
--- a/netwerk/sctp/src/moz.build
+++ b/netwerk/sctp/src/moz.build
@@ -86,7 +86,5 @@ if CONFIG['OS_TARGET'] == 'OpenBSD':
 if CONFIG['OS_TARGET'] == 'DragonFly':
     DEFINES['__DragonFly__'] = False
 
-NO_PGO = True # Don't PGO
-
 if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
     CFLAGS += ['-std=gnu99']
diff --git a/xpcom/reflect/xptcall/md/unix/moz.build b/xpcom/reflect/xptcall/md/unix/moz.build
index 4c2c35f53631..6fdb19ad1d90 100644
--- a/xpcom/reflect/xptcall/md/unix/moz.build
+++ b/xpcom/reflect/xptcall/md/unix/moz.build
@@ -332,5 +332,3 @@ LOCAL_INCLUDES += [
     '../..',
     '/xpcom/reflect/xptinfo',
 ]
-
-NO_PGO = True
diff --git a/xpcom/reflect/xptcall/md/win32/moz.build b/xpcom/reflect/xptcall/md/win32/moz.build
index 7c91bbcace14..6e782e70368f 100644
--- a/xpcom/reflect/xptcall/md/win32/moz.build
+++ b/xpcom/reflect/xptcall/md/win32/moz.build
@@ -34,7 +34,6 @@ else:
             'xptcinvoke_asm_x86_msvc.asm',
             'xptcstubs.cpp',
         ]
-        SOURCES['xptcinvoke.cpp'].no_pgo = True
         SOURCES['xptcinvoke_asm_x86_msvc.asm'].flags += ['-safeseh']
 
 FINAL_LIBRARY = 'xul'