diff --git a/kernel/Makefile b/kernel/Makefile
index a441bde7c..e81225075 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -5,6 +5,27 @@ endif
 TOPDIR	= ..
 include $(TOPDIR)/Makefile.system
 
+AVX2OPT = 
+ifeq ($(C_COMPILER), GCC)
+# AVX2 support was added in 4.7.0
+  GCCVERSIONGTEQ4 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \>= 4)
+  GCCMINORVERSIONGTEQ7 := $(shell expr `$(CC) -dumpversion | cut -f2 -d.` \>= 7)
+  ifeq ($(GCCVERSIONGTEQ4)$(GCCMINORVERSIONGTEQ7), 11)
+   AVX2OPT = -mavx2
+  endif
+endif
+ifeq ($(C_COMPILER), CLANG)
+# Any clang posing as gcc 4.2 should be new enough (3.4 or later)
+  GCCVERSIONGTEQ4 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \>= 4)
+  GCCMINORVERSIONGTEQ2 := $(shell expr `$(CC) -dumpversion | cut -f2 -d.` \>= 2)
+  ifeq ($(GCCVERSIONGTEQ4)$(GCCMINORVERSIONGTEQ2), 11)
+   AVX2OPT = -mavx2
+  endif
+endif
+ifdef NO_AVX2
+ AVX2OPT=
+endif
+
 ifdef TARGET_CORE
 ifeq ($(TARGET_CORE), SKYLAKEX)
  override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE) -march=skylake-avx512
@@ -16,8 +37,10 @@ ifeq ($(TARGET_CORE), SKYLAKEX)
    override CFLAGS += -fno-asynchronous-unwind-tables
   endif
  endif
+else ifeq ($(TARGET_CORE), HASWELL)
+ override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE) $(AVX2OPT)
 else
-override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE)
+ override CFLAGS += -DBUILD_KERNEL -DTABLE_NAME=gotoblas_$(TARGET_CORE)
 endif
 BUILD_KERNEL = 1
 KDIR =
diff --git a/kernel/x86_64/KERNEL.HASWELL b/kernel/x86_64/KERNEL.HASWELL
index 848de38df..422e6c315 100644
--- a/kernel/x86_64/KERNEL.HASWELL
+++ b/kernel/x86_64/KERNEL.HASWELL
@@ -33,9 +33,10 @@ ZAXPYKERNEL = zaxpy.c
 
 STRMMKERNEL    =  sgemm_kernel_16x4_haswell.S
 SGEMMKERNEL    =  sgemm_kernel_16x4_haswell.S
+SGEMM_BETA     =  sgemm_beta_skylakex.c
 SGEMMINCOPY    =  ../generic/gemm_ncopy_16.c
 SGEMMITCOPY    =  ../generic/gemm_tcopy_16.c
-SGEMMONCOPY    =  ../generic/gemm_ncopy_4.c
+SGEMMONCOPY    =  sgemm_ncopy_4_skylakex.c
 SGEMMOTCOPY    =  ../generic/gemm_tcopy_4.c
 SGEMMINCOPYOBJ =  sgemm_incopy$(TSUFFIX).$(SUFFIX)
 SGEMMITCOPYOBJ =  sgemm_itcopy$(TSUFFIX).$(SUFFIX)
diff --git a/kernel/x86_64/sgemm_beta_skylakex.c b/kernel/x86_64/sgemm_beta_skylakex.c
index 498c46f0d..cdc9c44be 100644
--- a/kernel/x86_64/sgemm_beta_skylakex.c
+++ b/kernel/x86_64/sgemm_beta_skylakex.c
@@ -61,30 +61,36 @@ int CNAME(BLASLONG m, BLASLONG n, BLASLONG dummy1, FLOAT beta,
   c_offset = c;
 
   if (beta == ZERO){
-    __m512 z_zero;
-    __m256 y_zero;
 
-    z_zero = _mm512_setzero_ps();
-    y_zero = _mm256_setzero_ps();
     j = n;
     do {
       c_offset1 = c_offset;
       c_offset += ldc;
 
       i = m;
-
+#ifdef __AVX2__
       while (i >= 32) {
+#ifdef __AVX512CD__
+	  __m512 z_zero = _mm512_setzero_ps();
 	  _mm512_storeu_ps(c_offset1, z_zero);
 	  _mm512_storeu_ps(c_offset1 + 16, z_zero);
+#else
+	  __m256 y_zero = _mm256_setzero_ps();
+	  _mm256_storeu_ps(c_offset1, y_zero);
+	  _mm256_storeu_ps(c_offset1 + 8, y_zero);
+	  _mm256_storeu_ps(c_offset1 + 16, y_zero);
+	  _mm256_storeu_ps(c_offset1 + 24, y_zero);
+#endif
 	  c_offset1 += 32;
 	  i -= 32;
       }
       while (i >= 8) {
+	    __m256 y_zero = _mm256_setzero_ps();
 	  _mm256_storeu_ps(c_offset1, y_zero);
 	  c_offset1 += 8;
 	  i -= 8;
       }
-
+#endif
       while (i > 0) {
 	  *c_offset1 = ZERO;
 	  c_offset1 ++;
diff --git a/kernel/x86_64/sgemm_ncopy_4_skylakex.c b/kernel/x86_64/sgemm_ncopy_4_skylakex.c
index 8577e3b38..6b2b0f5b1 100644
--- a/kernel/x86_64/sgemm_ncopy_4_skylakex.c
+++ b/kernel/x86_64/sgemm_ncopy_4_skylakex.c
@@ -49,8 +49,7 @@ int CNAME(BLASLONG m, BLASLONG n, FLOAT * __restrict a, BLASLONG lda, FLOAT * __
   FLOAT *b_offset;
   FLOAT  ctemp1,  ctemp2,  ctemp3,  ctemp4;
   FLOAT  ctemp5,  ctemp6,  ctemp7,  ctemp8;
-  FLOAT  ctemp9, ctemp10, ctemp11, ctemp12;
-  FLOAT ctemp13, ctemp14, ctemp15, ctemp16;
+  FLOAT  ctemp9,  ctemp13;
 
   a_offset = a;
   b_offset = b;