diff --git a/conf/Makefile.common b/conf/Makefile.common
index 4d38ff034..7ef171b2b 100644
--- a/conf/Makefile.common
+++ b/conf/Makefile.common
@@ -24,6 +24,8 @@ if COND_HAVE_PCI
   CFLAGS_PLATFORM += -DGRUB_HAS_PCI
 endif
 
+CPPFLAGS_GCRY_ASM = @CPPFLAGS_GCRY_ASM@
+
 # Other options
 
 CPPFLAGS_DEFAULT = -DGRUB_FILE=\"$(subst $(srcdir)/,,$<)\"
diff --git a/configure.ac b/configure.ac
index 1036638a9..1f391fa8e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1148,6 +1148,239 @@ if test "x$grub_cv_cc_fno_ident" = xyes; then
   TARGET_CFLAGS="$TARGET_CFLAGS -fno-ident"
 fi
 
+# Implementation of the --disable-amd64-as-feature-detection switch.
+AC_MSG_CHECKING([whether to enable AMD64 as(1) feature detection])
+if test x$target_cpu == xx86_64 -a x$platform == xefi; then
+  CPPFLAGS_GCRY_ASM="-D__x86_64 -DHAVE_CPU_ARCH_X86"
+  AC_ARG_ENABLE(amd64-as-feature-detection,
+    AS_HELP_STRING([--disable-amd64-as-feature-detection],
+      [Disable the auto-detection of AMD64 as(1) features]),
+    [amd64_as_feature_detection=$enableval],
+    [amd64_as_feature_detection=yes])
+else
+  CPPFLAGS_GCRY_ASM=
+  amd64_as_feature_detection=no
+fi
+AC_MSG_RESULT($amd64_as_feature_detection)
+
+#
+# Check whether GCC assembler supports features needed for libgcrypt amd64
+# implementations
+#
+if test $amd64_as_feature_detection = yes; then
+  AC_CACHE_CHECK([whether GCC assembler is compatible for amd64 assembly implementations],
+    [grub_cv_gcc_x86_platform_as_ok],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_x86_platform_as_ok="n/a"
+     else
+       grub_cv_gcc_x86_platform_as_ok=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[__asm__(
+             /* Test if '.type' and '.size' are supported.  */
+             /* These work only on ELF targets. */
+             ".text\n\t"
+             "asmfunc:\n\t"
+             ".size asmfunc,.-asmfunc;\n\t"
+             ".type asmfunc,@function;\n\t"
+             /* Test if assembler allows use of '/' for constant division
+              * (Solaris/x86 issue). If previous constant division check
+              * and "-Wa,--divide" workaround failed, this causes assembly
+              * to be disable on this machine. */
+              "xorl \$(123456789/12345678), %ebp;\n\t"
+         );
+         void asmfunc(void);]], [ asmfunc(); ])],
+       [grub_cv_gcc_x86_platform_as_ok=yes])
+     fi])
+  if test "$grub_cv_gcc_x86_platform_as_ok" = "yes"; then
+    # Define __PIC__ to ensure the assembly code use PIC instructions
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -D__PIC__=1 -DHAVE_COMPATIBLE_GCC_AMD64_PLATFORM_AS"
+  fi
+
+  #
+  # Check whether GCC assembler supports Intel syntax
+  #
+  AC_CACHE_CHECK([whether GCC assembler is compatible for Intel syntax assembly implementations],
+    [grub_cv_gcc_platform_as_ok_for_intel_syntax],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_platform_as_ok_for_intel_syntax="n/a"
+     else
+       grub_cv_gcc_platform_as_ok_for_intel_syntax=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[__asm__(
+             ".intel_syntax noprefix\n\t"
+             ".text\n\t"
+             "actest:\n\t"
+             "pxor xmm1, xmm7;\n\t"
+             "vperm2i128 ymm2, ymm3, ymm0, 1;\n\t"
+             "add eax, ebp;\n\t"
+             "rorx eax, ebp, 1;\n\t"
+             "sub eax, [esp + 4];\n\t"
+             "add dword ptr [esp + eax], 0b10101;\n\t"
+             ".att_syntax prefix\n\t"
+         );
+         void actest(void);]], [ actest(); ])],
+       [grub_cv_gcc_platform_as_ok_for_intel_syntax=yes])
+     fi])
+  if test "$grub_cv_gcc_platform_as_ok_for_intel_syntax" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_INTEL_SYNTAX_PLATFORM_AS"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports SSSE3 instructions
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports SSSE3 instructions],
+    [grub_cv_gcc_inline_asm_ssse3],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_ssse3="n/a"
+     else
+       grub_cv_gcc_inline_asm_ssse3=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[static unsigned char be_mask[16] __attribute__ ((aligned (16))) =
+           { 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };
+         void a(void) {
+           __asm__("pshufb %[mask], %%xmm2\n\t"::[mask]"m"(*be_mask):);
+         }]], [ a(); ] )],
+       [grub_cv_gcc_inline_asm_ssse3=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_ssse3" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_SSSE3"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports SHA Extensions instructions.
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports SHA Extensions instructions],
+    [grub_cv_gcc_inline_asm_shaext],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_shaext="n/a"
+     else
+       grub_cv_gcc_inline_asm_shaext=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[void a(void) {
+           __asm__("sha1rnds4 \$0, %%xmm1, %%xmm3\n\t":::"cc");
+           __asm__("sha1nexte %%xmm1, %%xmm3\n\t":::"cc");
+           __asm__("sha1msg1 %%xmm1, %%xmm3\n\t":::"cc");
+           __asm__("sha1msg2 %%xmm1, %%xmm3\n\t":::"cc");
+           __asm__("sha256rnds2 %%xmm0, %%xmm1, %%xmm3\n\t":::"cc");
+           __asm__("sha256msg1 %%xmm1, %%xmm3\n\t":::"cc");
+           __asm__("sha256msg2 %%xmm1, %%xmm3\n\t":::"cc");
+         }]], [ a(); ] )],
+       [grub_cv_gcc_inline_asm_shaext=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_shaext" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_SHAEXT -DENABLE_SHAEXT_SUPPORT"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports SSE4.1 instructions.
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports SSE4.1 instructions],
+    [grub_cv_gcc_inline_asm_sse41],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_sse41="n/a"
+     else
+       grub_cv_gcc_inline_asm_sse41=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[void a(void) {
+           int i;
+           __asm__("pextrd \$2, %%xmm0, %[out]\n\t" : [out] "=m" (i));
+         }]], [ a(); ] )],
+       [grub_cv_gcc_inline_asm_sse41=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_sse41" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_SSE41"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports AVX instructions
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports AVX instructions],
+    [grub_cv_gcc_inline_asm_avx],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_avx="n/a"
+     else
+       grub_cv_gcc_inline_asm_avx=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[void a(void) {
+           __asm__("xgetbv; vaesdeclast (%[mem]),%%xmm0,%%xmm7\n\t"::[mem]"r"(0):);
+         }]], [ a(); ] )],
+       [grub_cv_gcc_inline_asm_avx=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_avx" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_AVX"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports AVX2 instructions
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports AVX2 instructions],
+    [grub_cv_gcc_inline_asm_avx2],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_avx2="n/a"
+     else
+       grub_cv_gcc_inline_asm_avx2=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[void a(void) {
+           __asm__("xgetbv; vpbroadcastb %%xmm7,%%ymm1\n\t":::"cc");
+         }]], [ a(); ] )],
+       [grub_cv_gcc_inline_asm_avx2=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_avx2" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_AVX2"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports AVX512 instructions
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports AVX512 instructions],
+    [grub_cv_gcc_inline_asm_avx512],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_avx512="n/a"
+     else
+       grub_cv_gcc_inline_asm_avx512=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[void a(void) {
+           __asm__("xgetbv; vpopcntq %%zmm7, %%zmm1%{%%k1%}%{z%};\n\t":::"cc");
+           __asm__("vpexpandb %%zmm3, %%zmm1;\n\t":::"cc");
+           __asm__("vpxorq %%xmm7, %%xmm7, %%xmm7;\n\t":::"cc");
+           __asm__("vpxorq %%ymm7, %%ymm7, %%ymm7;\n\t":::"cc");
+           __asm__("vpxorq (%%eax)%{1to8%}, %%zmm7, %%zmm7;\n\t":::"cc");
+         }]], [ a(); ] )],
+       [grub_cv_gcc_inline_asm_avx512=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_avx512" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_AVX512"
+  fi
+
+  #
+  # Check whether GCC inline assembler supports BMI2 instructions
+  #
+  AC_CACHE_CHECK([whether GCC inline assembler supports BMI2 instructions],
+    [grub_cv_gcc_inline_asm_bmi2],
+    [if test "$target_cpu" != "x86_64" ; then
+       grub_cv_gcc_inline_asm_bmi2="n/a"
+     else
+       grub_cv_gcc_inline_asm_bmi2=no
+       AC_LINK_IFELSE([AC_LANG_PROGRAM(
+       [[unsigned int a(unsigned int x, unsigned int y) {
+           unsigned int tmp1, tmp2;
+           asm ("rorxl %2, %1, %0"
+                : "=r" (tmp1)
+                : "rm0" (x), "J" (32 - ((23) & 31)));
+           asm ("andnl %2, %1, %0"
+                : "=r" (tmp2)
+                : "r0" (x), "rm" (y));
+           return tmp1 + tmp2;
+         }]], [ a(1, 2); ] )],
+       [grub_cv_gcc_inline_asm_bmi2=yes])
+     fi])
+  if test "$grub_cv_gcc_inline_asm_bmi2" = "yes" ; then
+    CPPFLAGS_GCRY_ASM="$CPPFLAGS_GCRY_ASM -DHAVE_GCC_INLINE_ASM_BMI2"
+  fi
+fi
+
+AC_SUBST(CPPFLAGS_GCRY_ASM)
+
 CFLAGS="$TARGET_CFLAGS"