diff --git a/config/bulldozer/make_defs.mk b/config/bulldozer/make_defs.mk
index 06f7d8251..2e7c0db5a 100644
--- a/config/bulldozer/make_defs.mk
+++ b/config/bulldozer/make_defs.mk
@@ -75,7 +75,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/excavator/make_defs.mk b/config/excavator/make_defs.mk
index 48de8ed50..30c885601 100644
--- a/config/excavator/make_defs.mk
+++ b/config/excavator/make_defs.mk
@@ -75,7 +75,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/haswell/make_defs.mk b/config/haswell/make_defs.mk
index e33b2ad11..41b61540a 100644
--- a/config/haswell/make_defs.mk
+++ b/config/haswell/make_defs.mk
@@ -79,7 +79,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/knc/make_defs.mk b/config/knc/make_defs.mk
index ba2209c16..48b89159f 100644
--- a/config/knc/make_defs.mk
+++ b/config/knc/make_defs.mk
@@ -71,7 +71,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/knl/make_defs.mk b/config/knl/make_defs.mk
index f4165f788..e239a2fdf 100644
--- a/config/knl/make_defs.mk
+++ b/config/knl/make_defs.mk
@@ -99,7 +99,7 @@ endif
 # Note: We use AVX2 for reference kernels instead of AVX-512.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := -march=knl -mno-avx512f -mno-avx512pf -mno-avx512er -mno-avx512cd
+CRVECFLAGS     := -march=knl -mno-avx512f -mno-avx512pf -mno-avx512er -mno-avx512cd -funsafe-loop-optimizations
 else
 ifeq ($(CC_VENDOR),icc)
 CRVECFLAGS     := -xMIC-AVX512
diff --git a/config/penryn/make_defs.mk b/config/penryn/make_defs.mk
index 060c06609..175c8d5bf 100644
--- a/config/penryn/make_defs.mk
+++ b/config/penryn/make_defs.mk
@@ -79,7 +79,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/piledriver/make_defs.mk b/config/piledriver/make_defs.mk
index 425040692..c5313d76b 100644
--- a/config/piledriver/make_defs.mk
+++ b/config/piledriver/make_defs.mk
@@ -75,7 +75,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/sandybridge/make_defs.mk b/config/sandybridge/make_defs.mk
index e9e5f3be3..02fb4d641 100644
--- a/config/sandybridge/make_defs.mk
+++ b/config/sandybridge/make_defs.mk
@@ -79,7 +79,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/skx/make_defs.mk b/config/skx/make_defs.mk
index e9319e476..98c5ebd6f 100644
--- a/config/skx/make_defs.mk
+++ b/config/skx/make_defs.mk
@@ -89,7 +89,7 @@ endif
 # to overcome the AVX-512 frequency drop". (Issue #187)
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := -march=skylake-avx512 -mno-avx512f -mno-avx512vl -mno-avx512bw -mno-avx512dq -mno-avx512cd
+CRVECFLAGS     := -march=skylake-avx512 -mno-avx512f -mno-avx512vl -mno-avx512bw -mno-avx512dq -mno-avx512cd -funsafe-loop-optimizations
 else
 ifeq ($(CC_VENDOR),icc)
 CRVECFLAGS     := -xCORE-AVX2
diff --git a/config/steamroller/make_defs.mk b/config/steamroller/make_defs.mk
index 58315d7f5..351720296 100644
--- a/config/steamroller/make_defs.mk
+++ b/config/steamroller/make_defs.mk
@@ -75,7 +75,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif
diff --git a/config/zen/make_defs.mk b/config/zen/make_defs.mk
index 882ccfef9..f16d98836 100644
--- a/config/zen/make_defs.mk
+++ b/config/zen/make_defs.mk
@@ -62,7 +62,7 @@ endif
 # Flags specific to reference kernels.
 CROPTFLAGS     := $(CKOPTFLAGS)
 ifeq ($(CC_VENDOR),gcc)
-CRVECFLAGS     := $(CKVECFLAGS)
+CRVECFLAGS     := $(CKVECFLAGS) -funsafe-loop-optimizations
 else
 CRVECFLAGS     := $(CKVECFLAGS)
 endif