diff --git a/gfx/ycbcr/yuv_row_win.cpp b/gfx/ycbcr/yuv_row_win.cpp
--- a/gfx/ycbcr/yuv_row_win.cpp
+++ b/gfx/ycbcr/yuv_row_win.cpp
@@ -7,19 +7,21 @@
 
 #define kCoefficientsRgbU kCoefficientsRgbY + 2048
 #define kCoefficientsRgbV kCoefficientsRgbY + 4096
 
 extern "C" {
 
 #if defined(MOZILLA_MAY_SUPPORT_SSE) && defined(_M_IX86)
 #if defined(__clang__)
-// clang-cl may erroneously discard the symbol `kCoefficientsRgbY`
-// https://bugs.llvm.org/show_bug.cgi?id=35290
-volatile auto keep_kCoefficientsRgbY_alive = &kCoefficientsRgbY;
+// clang-cl has a bug where it doesn't mangle names in inline asm
+// so let's do the mangling in the preprocessor (ugh)
+// (but we still need to declare a dummy extern for the parser)
+extern void* _kCoefficientsRgbY;
+#define kCoefficientsRgbY _kCoefficientsRgbY
 #endif
 
 __declspec(naked)
 void FastConvertYUVToRGB32Row_SSE(const uint8* y_buf,
                                   const uint8* u_buf,
                                   const uint8* v_buf,
                                   uint8* rgb_buf,
                                   int width) {