diff --git a/common.mk b/common.mk
index 0578bd37b..abbbc0963 100644
--- a/common.mk
+++ b/common.mk
@@ -68,7 +68,9 @@ $(eval $(call store-var-for,CWARNFLAGS, $(1)))
 $(eval $(call store-var-for,CDBGFLAGS,  $(1)))
 $(eval $(call store-var-for,COPTFLAGS,  $(1)))
 $(eval $(call store-var-for,CKOPTFLAGS, $(1)))
-$(eval $(call store-var-for,CVECFLAGS,  $(1)))
+$(eval $(call store-var-for,CKVECFLAGS, $(1)))
+$(eval $(call store-var-for,CROPTFLAGS, $(1)))
+$(eval $(call store-var-for,CRVECFLAGS, $(1)))
 CONFIGS_INCL += $(1)
 endef
 
@@ -102,8 +104,8 @@ get-refinit-cflags-for = $(call load-var-for,COPTFLAGS,$(1)) \
                          $(call get-noopt-cflags-for,$(1)) \
                          -DBLIS_CNAME=$(1)
 
-get-refkern-cflags-for = $(call load-var-for,CKOPTFLAGS,$(1)) \
-                         $(call load-var-for,CVECFLAGS,$(1)) \
+get-refkern-cflags-for = $(call load-var-for,CROPTFLAGS,$(1)) \
+                         $(call load-var-for,CRVECFLAGS,$(1)) \
                          $(call get-noopt-cflags-for,$(1)) \
                          -DBLIS_CNAME=$(1)
 
@@ -114,7 +116,7 @@ get-frame-cflags-for   = $(call load-var-for,COPTFLAGS,$(1)) \
                          $(call get-noopt-cflags-for,$(1))
 
 get-kernel-cflags-for  = $(call load-var-for,CKOPTFLAGS,$(1)) \
-                         $(call load-var-for,CVECFLAGS,$(1)) \
+                         $(call load-var-for,CKVECFLAGS,$(1)) \
                          $(call get-noopt-cflags-for,$(1))
 
 get-noopt-text       = "(CFLAGS for no optimization)"
diff --git a/config/amd64/make_defs.mk b/config/amd64/make_defs.mk
index 08c215511..c2798c15a 100644
--- a/config/amd64/make_defs.mk
+++ b/config/amd64/make_defs.mk
@@ -68,15 +68,19 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver2
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver2
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver2
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver2
 else
 $(error gcc or clang are required for this configuration.)
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/arm32/make_defs.mk b/config/arm32/make_defs.mk
index 856f5dd19..2e0a85869 100644
--- a/config/arm32/make_defs.mk
+++ b/config/arm32/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -march=armv7-a
+CKVECFLAGS     := -march=armv7-a
 else
 $(error gcc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/arm64/make_defs.mk b/config/arm64/make_defs.mk
index c1b090dd6..2e46208b4 100644
--- a/config/arm64/make_defs.mk
+++ b/config/arm64/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -march=armv8-a
+CKVECFLAGS     := -march=armv8-a
 else
 $(error gcc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/bgq/make_defs.mk b/config/bgq/make_defs.mk
index 0278e78f3..f816b56c6 100644
--- a/config/bgq/make_defs.mk
+++ b/config/bgq/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),ibm)
-CVECFLAGS      := -qarch=qp -qtune=qp -qsimd=auto -qhot=level=1 -qprefetch -qunroll=yes -qnoipa
+CKVECFLAGS     := -qarch=qp -qtune=qp -qsimd=auto -qhot=level=1 -qprefetch -qunroll=yes -qnoipa
 else
 $(error xlc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Override the default value for LDFLAGS.
 LDFLAGS        := -L/bgsys/drivers/ppcfloor/spi/lib -lSPI -lSPI_cnk -qthreaded -qsmp=omp
 
diff --git a/config/bulldozer/make_defs.mk b/config/bulldozer/make_defs.mk
index 6d7bd9edb..0f0845b0f 100644
--- a/config/bulldozer/make_defs.mk
+++ b/config/bulldozer/make_defs.mk
@@ -68,15 +68,19 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma4 -march=bdver1
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma4 -march=bdver1
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma4 -march=bdver1
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma4 -march=bdver1
 else
 $(error gcc or clang are required for this configuration.)
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/cortexa15/make_defs.mk b/config/cortexa15/make_defs.mk
index ea9c168fa..90dbcf6af 100644
--- a/config/cortexa15/make_defs.mk
+++ b/config/cortexa15/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -march=armv7-a
+CKVECFLAGS     := -march=armv7-a
 else
 $(error gcc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/cortexa57/make_defs.mk b/config/cortexa57/make_defs.mk
index f3d3a9a8b..67d0aed06 100644
--- a/config/cortexa57/make_defs.mk
+++ b/config/cortexa57/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -march=armv8-a+fp+simd -mcpu=cortex-a57.cortex-a53
+CKVECFLAGS     := -march=armv8-a+fp+simd -mcpu=cortex-a57.cortex-a53
 else
 $(error gcc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/cortexa9/make_defs.mk b/config/cortexa9/make_defs.mk
index 7aa8d0ce6..09951d080 100644
--- a/config/cortexa9/make_defs.mk
+++ b/config/cortexa9/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -march=armv7-a
+CKVECFLAGS     := -march=armv7-a
 else
 $(error gcc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/excavator/make_defs.mk b/config/excavator/make_defs.mk
index 55645dc83..37d8c6f23 100644
--- a/config/excavator/make_defs.mk
+++ b/config/excavator/make_defs.mk
@@ -68,15 +68,19 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver4
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver4
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver4
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver4
 else
 $(error gcc or clang are required for this configuration.)
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/generic/make_defs.mk b/config/generic/make_defs.mk
index 801ffb5a0..d5d039a54 100644
--- a/config/generic/make_defs.mk
+++ b/config/generic/make_defs.mk
@@ -68,19 +68,23 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      :=
+CKVECFLAGS     :=
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      :=
+CKVECFLAGS     :=
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      :=
+CKVECFLAGS     :=
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/haswell/make_defs.mk b/config/haswell/make_defs.mk
index 0bf92294c..2bcf81274 100644
--- a/config/haswell/make_defs.mk
+++ b/config/haswell/make_defs.mk
@@ -68,19 +68,23 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mavx2 -mfma -mfpmath=sse -march=core-avx2
+CKVECFLAGS     := -mavx2 -mfma -mfpmath=sse -march=core-avx2
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xCORE-AVX2
+CKVECFLAGS     := -xCORE-AVX2
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mavx2 -mfma -mfpmath=sse -march=core-avx2
+CKVECFLAGS     := -mavx2 -mfma -mfpmath=sse -march=core-avx2
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/intel64/make_defs.mk b/config/intel64/make_defs.mk
index 773ea0587..267e3c0c4 100644
--- a/config/intel64/make_defs.mk
+++ b/config/intel64/make_defs.mk
@@ -68,19 +68,23 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mssse3 -mfpmath=sse -march=core2
+CKVECFLAGS     := -mssse3 -mfpmath=sse -march=core2
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xSSSE3
+CKVECFLAGS     := -xSSSE3
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mssse3 -mfpmath=sse -march=core2
+CKVECFLAGS     := -mssse3 -mfpmath=sse -march=core2
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/knc/make_defs.mk b/config/knc/make_defs.mk
index aed5f1304..af1b7e8ea 100644
--- a/config/knc/make_defs.mk
+++ b/config/knc/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := 
+CKVECFLAGS     := 
 else
 $(error icc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Override the default value for LDFLAGS.
 LDFLAGS        := -mmic
 
diff --git a/config/knl/make_defs.mk b/config/knl/make_defs.mk
index 5fa2f3b52..58a31b934 100644
--- a/config/knl/make_defs.mk
+++ b/config/knl/make_defs.mk
@@ -70,19 +70,23 @@ ifeq ($(DEBUG_TYPE),sde)
 # Note: The BLIS_DISABLE_MEMKIND macro definition will override
 # (undefine) the BLIS_ENABLE_MEMKIND macro definition.
 CPPROCFLAGS    += -DBLIS_DISABLE_MEMKIND
+# This value is normally set by configure and communicated to make via
+# config.mk, however, the make_defs.mk files (this file) get included
+# after config.mk, so this definition will override that earlier
+# definition.
 BLIS_ENABLE_MEMKIND := no
 endif
 
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mavx512f -mavx512pf -mfpmath=sse -march=knl
+CKVECFLAGS     := -mavx512f -mavx512pf -mfpmath=sse -march=knl
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xMIC-AVX512
+CKVECFLAGS     := -xMIC-AVX512
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mavx512f -mavx512pf -mfpmath=sse -march=knl
+CKVECFLAGS     := -mavx512f -mavx512pf -mfpmath=sse -march=knl
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
@@ -92,10 +96,15 @@ endif
 # The assembler on OS X won't recognize AVX512 without help.
 ifneq ($(CC_VENDOR),icc)
 ifeq ($(OS_NAME),Darwin)
-CVECFLAGS      += -Wa,-march=knl
+CKVECFLAGS     += -Wa,-march=knl
 endif
 endif
 
+# Flags specific to reference kernels.
+# Note: We use AVX2 for reference kernels instead of AVX-512.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := -mavx2 -mfma -mfpmath=sse -march=knl
+
 # Never use libmemkind with Intel SDE.
 ifneq ($(DEBUG_TYPE),sde)
 LDFLAGS        += -lmemkind
diff --git a/config/old/armv7a/make_defs.mk b/config/old/armv7a/make_defs.mk
index fd0d8980f..128cb0d3c 100644
--- a/config/old/armv7a/make_defs.mk
+++ b/config/old/armv7a/make_defs.mk
@@ -67,7 +67,7 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mfpu=vfpv3 -marm -march=armv7-a
+CKVECFLAGS     := -mfpu=vfpv3 -marm -march=armv7-a
 else
 $(error gcc is required for this configuration.)
 endif
diff --git a/config/old/emscripten/make_defs.mk b/config/old/emscripten/make_defs.mk
index 2fe526ecb..82f966d2b 100644
--- a/config/old/emscripten/make_defs.mk
+++ b/config/old/emscripten/make_defs.mk
@@ -54,7 +54,7 @@ CDBGFLAGS      := #-g4
 CWARNFLAGS     := -Wall -Wno-unused-function -Wfatal-errors
 COPTFLAGS      := -O2
 CKOPTFLAGS     := -O3
-CVECFLAGS      :=
+CKVECFLAGS     :=
 
 # --- Determine the archiver and related flags ---
 AR             := emar
diff --git a/config/old/loongson3a/make_defs.mk b/config/old/loongson3a/make_defs.mk
index 195d0ce36..cca01d995 100644
--- a/config/old/loongson3a/make_defs.mk
+++ b/config/old/loongson3a/make_defs.mk
@@ -67,7 +67,7 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -march=loongson3a
+CKVECFLAGS     := -march=loongson3a
 else
 $(error gcc is required for this configuration.)
 endif
diff --git a/config/old/newarch/make_defs.mk b/config/old/newarch/make_defs.mk
index 64d53c49e..58af7001d 100644
--- a/config/old/newarch/make_defs.mk
+++ b/config/old/newarch/make_defs.mk
@@ -67,13 +67,13 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := 
+CKVECFLAGS     := 
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := 
+CKVECFLAGS     := 
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := 
+CKVECFLAGS     := 
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
diff --git a/config/old/pnacl/make_defs.mk b/config/old/pnacl/make_defs.mk
index b060ba9cb..efc46527f 100644
--- a/config/old/pnacl/make_defs.mk
+++ b/config/old/pnacl/make_defs.mk
@@ -54,7 +54,7 @@ CDBGFLAGS      := -g
 CWARNFLAGS     := -Wall -Wno-unused-function -Wfatal-errors
 COPTFLAGS      := -O3
 CKOPTFLAGS     := $(COPTFLAGS) -ffast-math
-CVECFLAGS      :=
+CKVECFLAGS     :=
 
 # --- Determine the archiver and related flags ---
 AR             := pnacl-ar
diff --git a/config/penryn/make_defs.mk b/config/penryn/make_defs.mk
index c1076de95..9313f89dc 100644
--- a/config/penryn/make_defs.mk
+++ b/config/penryn/make_defs.mk
@@ -68,19 +68,23 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mssse3 -mfpmath=sse -march=core2
+CKVECFLAGS     := -mssse3 -mfpmath=sse -march=core2
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xSSSE3
+CKVECFLAGS     := -xSSSE3
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mssse3 -mfpmath=sse -march=core2
+CKVECFLAGS     := -mssse3 -mfpmath=sse -march=core2
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/piledriver/make_defs.mk b/config/piledriver/make_defs.mk
index e99a8a817..e1c89817f 100644
--- a/config/piledriver/make_defs.mk
+++ b/config/piledriver/make_defs.mk
@@ -68,15 +68,19 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver2
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver2
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver2
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver2
 else
 $(error gcc or clang are required for this configuration.)
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/power7/make_defs.mk b/config/power7/make_defs.mk
index 645da770a..6007b557f 100644
--- a/config/power7/make_defs.mk
+++ b/config/power7/make_defs.mk
@@ -68,11 +68,15 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mvsx
+CKVECFLAGS     := -mvsx
 else
 $(error gcc is required for this configuration.)
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/sandybridge/make_defs.mk b/config/sandybridge/make_defs.mk
index ec6225c24..0acfa6200 100644
--- a/config/sandybridge/make_defs.mk
+++ b/config/sandybridge/make_defs.mk
@@ -68,19 +68,23 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mavx -mfpmath=sse -march=corei7-avx
+CKVECFLAGS     := -mavx -mfpmath=sse -march=corei7-avx
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xAVX
+CKVECFLAGS     := -xAVX
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mavx -mfpmath=sse -march=corei7-avx
+CKVECFLAGS     := -mavx -mfpmath=sse -march=corei7-avx
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/skx/make_defs.mk b/config/skx/make_defs.mk
index fe4110d09..0e8fcf596 100644
--- a/config/skx/make_defs.mk
+++ b/config/skx/make_defs.mk
@@ -68,13 +68,13 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mavx512f -mavx512dq -mavx512bw -mavx512vl -mfpmath=sse -march=skylake-avx512
+CKVECFLAGS     := -mavx512f -mavx512dq -mavx512bw -mavx512vl -mfpmath=sse -march=skylake-avx512
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xCORE-AVX512
+CKVECFLAGS     := -xCORE-AVX512
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mavx512f -mavx512dq -mavx512bw -mavx512vl -mfpmath=sse -march=skylake-avx512
+CKVECFLAGS     := -mavx512f -mavx512dq -mavx512bw -mavx512vl -mfpmath=sse -march=skylake-avx512
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
@@ -84,10 +84,17 @@ endif
 # The assembler on OS X won't recognize AVX512 without help
 ifneq ($(CC_VENDOR),icc)
 ifeq ($(OS_NAME),Darwin)
-CVECFLAGS      += -Wa,-march=skylake-avx512
+CKVECFLAGS     += -Wa,-march=skylake-avx512
 endif
 endif
 
+# Flags specific to reference kernels.
+# Note: We use AVX2 for reference kernels because, as Jeff Hammond says,
+# reference kernel code "is not going to achieve high enough SIMD utilization
+# to overcome the AVX-512 frequency drop". (Issue #187)
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := -mavx2 -mfma -mfpmath=sse -march=skylake-avx512
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/steamroller/make_defs.mk b/config/steamroller/make_defs.mk
index dc5ccf47a..2baf7e8a4 100644
--- a/config/steamroller/make_defs.mk
+++ b/config/steamroller/make_defs.mk
@@ -68,15 +68,19 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver2
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver2
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mfpmath=sse -mavx -mfma -march=bdver2
+CKVECFLAGS     := -mfpmath=sse -mavx -mfma -march=bdver2
 else
 $(error gcc or clang are required for this configuration.)
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/template/make_defs.mk b/config/template/make_defs.mk
index abd934569..db616d0c9 100644
--- a/config/template/make_defs.mk
+++ b/config/template/make_defs.mk
@@ -67,6 +67,10 @@ endif
 
 CKOPTFLAGS     := $(COPTFLAGS)
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/x86_64/make_defs.mk b/config/x86_64/make_defs.mk
index 2db7a8b87..953c48fe9 100644
--- a/config/x86_64/make_defs.mk
+++ b/config/x86_64/make_defs.mk
@@ -68,19 +68,23 @@ endif
 CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
-CVECFLAGS      := -mssse3 -mfpmath=sse -march=core2
+CKVECFLAGS     := -mssse3 -mfpmath=sse -march=core2
 else
 ifeq ($(CC_VENDOR),icc)
-CVECFLAGS      := -xSSE3
+CKVECFLAGS     := -xSSE3
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mssse3 -mfpmath=sse -march=core2
+CKVECFLAGS     := -mssse3 -mfpmath=sse -march=core2
 else
 $(error gcc, icc, or clang is required for this configuration.)
 endif
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))
diff --git a/config/zen/make_defs.mk b/config/zen/make_defs.mk
index f2a4eb49d..519fab101 100644
--- a/config/zen/make_defs.mk
+++ b/config/zen/make_defs.mk
@@ -69,18 +69,22 @@ CKOPTFLAGS     := $(COPTFLAGS)
 
 ifeq ($(CC_VENDOR),gcc)
 # gcc 6.0 (clang 4.0) or later:
-#CVECFLAGS      := -mavx2 -mfpmath=sse -mfma -march=znver1
+#CKVECFLAGS     := -mavx2 -mfpmath=sse -mfma -march=znver1
 # gcc 4.9 (clang 3.5) or later:
 # possibly add zen-specific instructions: -mclzero -madx -mrdseed -mmwaitx -msha -mxsavec -mxsaves -mclflushopt -mpopcnt
-CVECFLAGS      := -mavx2 -mfpmath=sse -mfma -march=bdver4 -mno-fma4 -mno-tbm -mno-xop -mno-lwp
+CKVECFLAGS     := -mavx2 -mfpmath=sse -mfma -march=bdver4 -mno-fma4 -mno-tbm -mno-xop -mno-lwp
 else
 ifeq ($(CC_VENDOR),clang)
-CVECFLAGS      := -mavx2 -mfpmath=sse -mfma -march=bdver4 -mno-fma4 -mno-tbm -mno-xop -mno-lwp
+CKVECFLAGS     := -mavx2 -mfpmath=sse -mfma -march=bdver4 -mno-fma4 -mno-tbm -mno-xop -mno-lwp
 else
 $(error gcc or clang are required for this configuration.)
 endif
 endif
 
+# Flags specific to reference kernels.
+CROPTFLAGS     := $(CKOPTFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS)
+
 # Store all of the variables here to new variables containing the
 # configuration name.
 $(eval $(call store-make-defs,$(THIS_CONFIG)))