+if test "$ARCH" = "aarch64" ; then
+trycppif __AARCH64EB__ "$t" && SUBARCH=${SUBARCH}_be
+fi
+
+if test "$ARCH" = "m68k" ; then
+if trycppif "__HAVE_68881__" ; then : ;
+elif trycppif "__mcffpu__" ; then SUBARCH="-fp64"
+else SUBARCH="-sf"
+fi
+fi
+
+if test "$ARCH" = "mips" ; then
+trycppif "__mips_isa_rev >= 6" "$t" && SUBARCH=${SUBARCH}r6
+trycppif "_MIPSEL || __MIPSEL || __MIPSEL__" "$t" && SUBARCH=${SUBARCH}el
+trycppif __mips_soft_float "$t" && SUBARCH=${SUBARCH}-sf
+fi
+
+if test "$ARCH" = "mips64" ; then
+trycppif "_MIPS_SIM != _ABI64" "$t" && ARCH=mipsn32
+trycppif "__mips_isa_rev >= 6" "$t" && SUBARCH=${SUBARCH}r6
+trycppif "_MIPSEL || __MIPSEL || __MIPSEL__" "$t" && SUBARCH=${SUBARCH}el
+trycppif __mips_soft_float "$t" && SUBARCH=${SUBARCH}-sf
+fi
+
+if test "$ARCH" = "powerpc" ; then
+trycppif "_SOFT_FLOAT || __NO_FPRS__" "$t" && SUBARCH=${SUBARCH}-sf
+printf "checking whether compiler can use 'd' constraint in asm... "
+echo 'double f(double x) { __asm__ ("fabs %0, %1" : "=d"(x) : "d"(x)); return x; }' > "$tmpc"
+if $CC $CFLAGS_C99FSE $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+printf "yes\n"
+else
+printf "no\n"
+CFLAGS_AUTO="$CFLAGS_AUTO -DBROKEN_PPC_D_ASM"
+CFLAGS_AUTO="${CFLAGS_AUTO# }"
+fi
+fi
+
+test "$ARCH" = "microblaze" && trycppif __MICROBLAZEEL__ "$t" \
+&& SUBARCH=${SUBARCH}el
+
+if test "$ARCH" = "powerpc64" ; then
+trycppif "_CALL_ELF == 2" "$t" || fail "$0: error: unsupported powerpc64 ABI"
+trycppif __LITTLE_ENDIAN__ "$t" && SUBARCH=${SUBARCH}le
+trycppif _SOFT_FLOAT "$t" && fail "$0: error: soft-float not supported on powerpc64"
+fi
+
+if test "$ARCH" = "riscv64" ; then
+trycppif __riscv_float_abi_soft "$t" && SUBARCH=${SUBARCH}-sf
+trycppif __riscv_float_abi_single "$t" && SUBARCH=${SUBARCH}-sp
+fi
+
+if test "$ARCH" = "sh" ; then
+tryflag CFLAGS_AUTO -Wa,--isa=any
+trycppif __BIG_ENDIAN__ "$t" && SUBARCH=${SUBARCH}eb
+if trycppif "__SH_FPU_ANY__ || __SH4__" "$t" ; then
+# Some sh configurations are broken and replace double with float
+# rather than using softfloat when the fpu is present but only
+# supports single precision. Reject them.
+printf "checking whether compiler's double type is IEEE double... "
+echo 'typedef char dblcheck[(int)sizeof(double)-5];' > "$tmpc"
+if $CC $CFLAGS_C99FSE $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+printf "yes\n"
+else
+printf "no\n"
+fail "$0: error: compiler's floating point configuration is unsupported"
+fi
+else
+SUBARCH=${SUBARCH}-nofpu
+fi
+if trycppif __SH_FDPIC__ "$t" ; then
+SUBARCH=${SUBARCH}-fdpic
+fi
+fi
+
+test "$SUBARCH" \
+&& printf "configured for %s variant: %s\n" "$ARCH" "$ARCH$SUBARCH"
+
+#
+# Some archs (powerpc) have different possible long double formats
+# that the compiler can be configured for. The logic for whether this
+# is supported is in bits/float.h; in general, it is not. We need to
+# check for mismatches here or code in printf, strotd, and scanf will
+# be dangerously incorrect because it depends on (1) the macros being
+# correct, and (2) IEEE semantics.
+#
+printf "checking whether compiler's long double definition matches float.h... "
+echo '#include <float.h>' > "$tmpc"
+echo '#define C(m,s) (m==LDBL_MANT_DIG && s==sizeof(long double))' >> "$tmpc"
+echo 'typedef char ldcheck[(C(53,8)||C(64,12)||C(64,16)||C(113,16))*2-1];' >> "$tmpc"
+if $CC $CFLAGS_C99FSE \
+ -I$srcdir/arch/$ARCH -I$srcdir/arch/generic -I$srcdir/include \
+ $CPPFLAGS $CFLAGS -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+printf "yes\n"
+else
+printf "no\n"
+fail "$0: error: unsupported long double type"
+fi
+
+#
+# Some build systems globally pass in broken CFLAGS like -ffast-math
+# for all packages. On recent GCC we can detect this and error out
+# early rather than producing a seriously-broken math library.
+#
+if trycppif "__FAST_MATH__" \
+ "$CFLAGS_C99FSE $CPPFLAGS $CFLAGS" ; then
+fail "$0: error: compiler has broken floating point; check CFLAGS"
+fi