diff --git a/CLOBBER b/CLOBBER
index d4cdfaff33de..3f6f0c390eed 100644
--- a/CLOBBER
+++ b/CLOBBER
@@ -22,4 +22,4 @@
 # changes to stick? As of bug 928195, this shouldn't be necessary! Please
 # don't change CLOBBER for WebIDL changes any more.
 
-Merge day clobber
\ No newline at end of file
+Bug 1551084 - Part 2. Make QCMS transform files use C++. r=miko
diff --git a/gfx/qcms/moz.build b/gfx/qcms/moz.build
index 83ab2cc1c365..f553476479fc 100644
--- a/gfx/qcms/moz.build
+++ b/gfx/qcms/moz.build
@@ -13,7 +13,7 @@ SOURCES += [
     'chain.c',
     'iccread.c',
     'matrix.c',
-    'transform.c',
+    'transform.cpp',
     'transform_util.c',
 ]
 
@@ -36,16 +36,16 @@ elif CONFIG['HAVE_ALTIVEC']:
     use_altivec = True
 
 if use_sse1:
-    SOURCES += ['transform-sse1.c']
-    SOURCES['transform-sse1.c'].flags += CONFIG['SSE_FLAGS']
+    SOURCES += ['transform-sse1.cpp']
+    SOURCES['transform-sse1.cpp'].flags += CONFIG['SSE_FLAGS']
 
 if use_sse2:
     SOURCES += ['transform-sse2.cpp']
     SOURCES['transform-sse2.cpp'].flags += CONFIG['SSE2_FLAGS']
 
 if use_altivec:
-    SOURCES += ['transform-altivec.c']
-    SOURCES['transform-altivec.c'].flags += ['-maltivec']
+    SOURCES += ['transform-altivec.cpp']
+    SOURCES['transform-altivec.cpp'].flags += ['-maltivec']
 
 include('/tools/fuzzing/libfuzzer-config.mozbuild')
 
diff --git a/gfx/qcms/transform-altivec.c b/gfx/qcms/transform-altivec.cpp
similarity index 100%
rename from gfx/qcms/transform-altivec.c
rename to gfx/qcms/transform-altivec.cpp
diff --git a/gfx/qcms/transform-sse1.c b/gfx/qcms/transform-sse1.cpp
similarity index 100%
rename from gfx/qcms/transform-sse1.c
rename to gfx/qcms/transform-sse1.cpp
diff --git a/gfx/qcms/transform-sse2.c b/gfx/qcms/transform-sse2.cpp
similarity index 100%
rename from gfx/qcms/transform-sse2.c
rename to gfx/qcms/transform-sse2.cpp
diff --git a/gfx/qcms/transform.c b/gfx/qcms/transform.cpp
similarity index 100%
rename from gfx/qcms/transform.c
rename to gfx/qcms/transform.cpp