Index: head/lib/libclang_rt/Makefile.inc
===================================================================
--- head/lib/libclang_rt/Makefile.inc
+++ head/lib/libclang_rt/Makefile.inc
@@ -32,7 +32,7 @@
 CFLAGS+=	-fno-builtin
 CFLAGS+=	-fno-exceptions
 CXXFLAGS+=	-fno-rtti
-.if ${COMPILER_TYPE} == clang && ${COMPILER_VERSION} >= 30700
+.if ${COMPILER_TYPE} == clang
 CFLAGS+=	-fno-sanitize=safe-stack
 .endif
 CFLAGS+=	-fno-stack-protector
Index: head/lib/libthr/Makefile
===================================================================
--- head/lib/libthr/Makefile
+++ head/lib/libthr/Makefile
@@ -29,10 +29,7 @@
 
 CFLAGS.thr_stack.c+=	-Wno-cast-align
 CFLAGS.rtld_malloc.c+=	-Wno-cast-align
-.include <bsd.compiler.mk>
-.if !(${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} < 40300)
 CFLAGS.thr_symbols.c+=	-Wno-missing-variable-declarations
-.endif
 
 .ifndef NO_THREAD_UNWIND_STACK
 CFLAGS+=-fexceptions
Index: head/lib/msun/Makefile
===================================================================
--- head/lib/msun/Makefile
+++ head/lib/msun/Makefile
@@ -108,13 +108,13 @@
 	s_nextafterl.c s_nexttoward.c s_remquol.c s_rintl.c s_roundl.c \
 	s_scalbnl.c s_sinl.c s_sincosl.c \
 	s_tanhl.c s_tanl.c s_truncl.c w_cabsl.c
-# Work around this warning from gcc 6:
+# Work around this warning from gcc:
 #     lib/msun/ld80/e_powl.c:275:1: error: floating constant exceeds range of
 #     'long double' [-Werror=overflow]
 #     if( y >= LDBL_MAX )
 # See also: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=130067
 .include <bsd.compiler.mk>
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60000
+.if ${COMPILER_TYPE} == "gcc"
 CFLAGS.e_powl.c+= -Wno-error=overflow
 .endif
 .endif
Index: head/libexec/rtld-elf/Makefile
===================================================================
--- head/libexec/rtld-elf/Makefile
+++ head/libexec/rtld-elf/Makefile
@@ -90,8 +90,4 @@
 # GCC warns about redeclarations even though they have __exported
 # and are therefore not identical to the ones from the system headers.
 CFLAGS+=	-Wno-redundant-decls
-.if ${COMPILER_VERSION} < 40300
-# Silence -Wshadow false positives in ancient GCC
-CFLAGS+=	-Wno-shadow
-.endif
 .endif
Index: head/libexec/tftpd/tests/Makefile
===================================================================
--- head/libexec/tftpd/tests/Makefile
+++ head/libexec/tftpd/tests/Makefile
@@ -2,11 +2,8 @@
 
 .include <bsd.own.mk>
 
-# Skip on GCC 4.2, because it lacks __COUNTER__
-.if ${COMPILER_TYPE} != "gcc" || ${COMPILER_VERSION} >= 40300
 ATF_TESTS_C=	functional
 TEST_METADATA.functional+=	timeout=15
-.endif
 
 LIBADD=	util
 WARNS?=	6
Index: head/share/mk/bsd.compiler.mk
===================================================================
--- head/share/mk/bsd.compiler.mk
+++ head/share/mk/bsd.compiler.mk
@@ -205,20 +205,12 @@
 ${X_}COMPILER_RESOURCE_DIR!=	${${cc}:N${CCACHE_BIN}} -print-resource-dir 2>/dev/null || echo unknown
 .endif
 
-${X_}COMPILER_FEATURES=
-.if (${${X_}COMPILER_TYPE} == "clang" && ${${X_}COMPILER_VERSION} >= 30300) || \
-	(${${X_}COMPILER_TYPE} == "gcc" && ${${X_}COMPILER_VERSION} >= 40800)
-${X_}COMPILER_FEATURES+=	c++11
-.endif
-.if (${${X_}COMPILER_TYPE} == "clang" && ${${X_}COMPILER_VERSION} >= 30400) || \
-	(${${X_}COMPILER_TYPE} == "gcc" && ${${X_}COMPILER_VERSION} >= 50000)
-${X_}COMPILER_FEATURES+=	c++14
-.endif
-.if (${${X_}COMPILER_TYPE} == "clang" && ${${X_}COMPILER_VERSION} >= 50000) || \
+${X_}COMPILER_FEATURES=		c++11 c++14
+.if ${${X_}COMPILER_TYPE} == "clang" || \
 	(${${X_}COMPILER_TYPE} == "gcc" && ${${X_}COMPILER_VERSION} >= 70000)
 ${X_}COMPILER_FEATURES+=	c++17
 .endif
-.if ${${X_}COMPILER_TYPE} == "clang" && ${${X_}COMPILER_VERSION} >= 60000
+.if ${${X_}COMPILER_TYPE} == "clang"
 ${X_}COMPILER_FEATURES+=	retpoline
 .endif
 
Index: head/share/mk/bsd.sys.mk
===================================================================
--- head/share/mk/bsd.sys.mk
+++ head/share/mk/bsd.sys.mk
@@ -6,8 +6,7 @@
 # Enable various levels of compiler warning checks.  These may be
 # overridden (e.g. if using a non-gcc compiler) by defining MK_WARNS=no.
 
-# for 4.2.1 GCC:   http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Warning-Options.html
-# for current GCC: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
+# for GCC:   https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
 # for clang: https://clang.llvm.org/docs/DiagnosticsReference.html
 
 .include <bsd.compiler.mk>
@@ -29,15 +28,6 @@
 CXXFLAGS+=	-std=${CXXSTD}
 .endif
 
-#
-# Turn off -Werror for gcc 4.2.1. The compiler is on the glide path out of the
-# system, and any warnings specific to it are no longer relevant as there are
-# too many false positives.
-#
-.if ${COMPILER_VERSION} <  50000
-NO_WERROR.gcc=	yes
-.endif
-
 # -pedantic is problematic because it also imposes namespace restrictions
 #CFLAGS+=	-pedantic
 .if defined(WARNS)
@@ -81,19 +71,13 @@
 # is set to low values, these have to be disabled explicitly.
 .if ${WARNS} <= 6
 CWARNFLAGS.clang+=	-Wno-empty-body -Wno-string-plus-int
-.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30400
 CWARNFLAGS.clang+=	-Wno-unused-const-variable
-.endif
 .endif # WARNS <= 6
 .if ${WARNS} <= 3
 CWARNFLAGS.clang+=	-Wno-tautological-compare -Wno-unused-value\
 		-Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion
-.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
 CWARNFLAGS.clang+=	-Wno-unused-local-typedef
-.endif
-.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 40000
 CWARNFLAGS.clang+=	-Wno-address-of-packed-member
-.endif
 .if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 90100
 CWARNFLAGS.gcc+=	-Wno-address-of-packed-member
 .endif
@@ -113,7 +97,7 @@
 .endif # NO_WARRAY_BOUNDS
 .if defined(NO_WMISLEADING_INDENTATION) && \
     ((${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 100000) || \
-     (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60100))
+      ${COMPILER_TYPE} == "gcc")
 CWARNFLAGS+=		-Wno-misleading-indentation
 .endif # NO_WMISLEADING_INDENTATION
 .endif # WARNS
@@ -137,8 +121,10 @@
 CWARNFLAGS+=	-Wno-format
 .endif # NO_WFORMAT || NO_WFORMAT.${COMPILER_TYPE}
 
-# GCC 5.2.0
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 50200
+# GCC
+# We should clean up warnings produced with these flags.
+# They were originally added as a quick hack to enable gcc5/6.
+.if ${COMPILER_TYPE} == "gcc"
 CWARNFLAGS+=	-Wno-error=address			\
 		-Wno-error=array-bounds			\
 		-Wno-error=attributes			\
@@ -150,23 +136,18 @@
 		-Wno-error=extra			\
 		-Wno-error=inline			\
 		-Wno-error=logical-not-parentheses	\
+		-Wno-error=nonnull-compare		\
+		-Wno-error=shift-negative-value		\
 		-Wno-error=strict-aliasing		\
+		-Wno-error=tautological-compare		\
 		-Wno-error=uninitialized		\
 		-Wno-error=unused-but-set-variable	\
+		-Wno-error=unused-const-variable	\
 		-Wno-error=unused-function		\
 		-Wno-error=unused-value
-.endif
 
-# GCC 6.1.0
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60100
-CWARNFLAGS+=	-Wno-error=nonnull-compare		\
-		-Wno-error=shift-negative-value		\
-		-Wno-error=tautological-compare		\
-		-Wno-error=unused-const-variable
-.endif
-
 # GCC 7.1.0
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 70100
+.if ${COMPILER_VERSION} >= 70100
 CWARNFLAGS+=	-Wno-error=bool-operation		\
 		-Wno-error=deprecated			\
 		-Wno-error=expansion-to-defined		\
@@ -182,7 +163,7 @@
 .endif
 
 # GCC 8.1.0
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 80100
+.if ${COMPILER_VERSION} >= 80100
 CWARNFLAGS+=	-Wno-error=aggressive-loop-optimizations	\
 		-Wno-error=cast-function-type			\
 		-Wno-error=catch-value				\
@@ -191,9 +172,10 @@
 		-Wno-error=sizeof-pointer-memaccess		\
 		-Wno-error=stringop-truncation
 .endif
+.endif	# gcc
 
 # How to handle FreeBSD custom printf format specifiers.
-.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
+.if ${COMPILER_TYPE} == "clang"
 FORMAT_EXTENSIONS=	-D__printf__=__freebsd_kprintf__
 .else
 FORMAT_EXTENSIONS=	-fformat-extensions
@@ -223,11 +205,7 @@
 
 CLANG_OPT_SMALL= -mstack-alignment=8 -mllvm -inline-threshold=3\
 		 -mllvm -simplifycfg-dup-ret
-.if ${COMPILER_VERSION} >= 30500 && ${COMPILER_VERSION} < 30700
-CLANG_OPT_SMALL+= -mllvm -enable-gvn=false
-.else
 CLANG_OPT_SMALL+= -mllvm -enable-load-pre=false
-.endif
 CFLAGS.clang+=	 -Qunused-arguments
 # The libc++ headers use c++11 extensions.  These are normally silenced because
 # they are treated as system headers, but we explicitly disable that warning
@@ -238,14 +216,8 @@
 
 .if ${MK_SSP} != "no" && \
     ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
-.if (${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30500) || \
-    (${COMPILER_TYPE} == "gcc" && \
-     (${COMPILER_VERSION} == 40201 || ${COMPILER_VERSION} >= 40900))
 # Don't use -Wstack-protector as it breaks world with -Werror.
 SSP_CFLAGS?=	-fstack-protector-strong
-.else
-SSP_CFLAGS?=	-fstack-protector
-.endif
 CFLAGS+=	${SSP_CFLAGS}
 .endif # SSP && !ARM && !MIPS
 
Index: head/stand/arm/uboot/Makefile
===================================================================
--- head/stand/arm/uboot/Makefile
+++ head/stand/arm/uboot/Makefile
@@ -24,7 +24,7 @@
 # Architecture-specific loader code
 SRCS=		start.S conf.c self_reloc.c vers.c
 
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} > 40201
+.if ${COMPILER_TYPE} == "gcc"
 CWARNFLAGS.self_reloc.c+=	-Wno-error=maybe-uninitialized
 .endif
 
Index: head/stand/defs.mk
===================================================================
--- head/stand/defs.mk
+++ head/stand/defs.mk
@@ -143,11 +143,7 @@
 # Do not generate movt/movw, because the relocation fixup for them does not
 # translate to the -Bsymbolic -pie format required by self_reloc() in loader(8).
 # Also, the fpu is not available in a standalone environment.
-.if ${COMPILER_VERSION} < 30800
-CFLAGS.clang+=	-mllvm -arm-use-movt=0
-.else
 CFLAGS.clang+=	-mno-movt
-.endif
 CFLAGS.clang+=  -mfpu=none
 CFLAGS+=	-fPIC
 .endif
Index: head/stand/efi/Makefile
===================================================================
--- head/stand/efi/Makefile
+++ head/stand/efi/Makefile
@@ -4,16 +4,10 @@
 
 .include <bsd.init.mk>
 
-# In-tree GCC does not support __attribute__((ms_abi)), but gcc newer
-# than 4.5 supports it.
-.if ${COMPILER_TYPE} != "gcc" || ${COMPILER_VERSION} >= 40500
-
 SUBDIR.${MK_FDT}+=	fdt
 SUBDIR.yes+=	libefi boot1 gptboot
 SUBDIR.${MK_FORTH}+= loader_4th
 SUBDIR.${MK_LOADER_LUA}+= loader_lua
 SUBDIR.yes+=	loader_simp
-
-.endif # ${COMPILER_TYPE} != "gcc" || ${COMPILER_VERSION} >= 40500
 
 .include <bsd.subdir.mk>
Index: head/stand/efi/boot1/Makefile
===================================================================
--- head/stand/efi/boot1/Makefile
+++ head/stand/efi/boot1/Makefile
@@ -42,10 +42,6 @@
 CFLAGS+=	-DEFI_ZFS_BOOT
 .endif
 
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} > 40201
-CWARNFLAGS.self_reloc.c+=	-Wno-error=maybe-uninitialized
-.endif
-
 CFLAGS+=	-I${EFIINC}
 CFLAGS+=	-I${EFIINCMD}
 CFLAGS+=	-I${SYSDIR}/contrib/dev/acpica/include
Index: head/stand/efi/loader/Makefile
===================================================================
--- head/stand/efi/loader/Makefile
+++ head/stand/efi/loader/Makefile
@@ -31,10 +31,6 @@
 HAVE_ZFS=	yes
 .endif
 
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} > 40201
-CWARNFLAGS.self_reloc.c+=	-Wno-error=maybe-uninitialized
-.endif
-
 # We implement a slightly non-standard %S in that it always takes a
 # CHAR16 that's common in UEFI-land instead of a wchar_t. This only
 # seems to matter on arm64 where wchar_t defaults to an int instead
Index: head/stand/i386/boot2/Makefile
===================================================================
--- head/stand/i386/boot2/Makefile
+++ head/stand/i386/boot2/Makefile
@@ -37,9 +37,6 @@
 CFLAGS.gcc+=	-Os \
 		-fno-asynchronous-unwind-tables \
 		--param max-inline-insns-single=100
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} <= 40201
-CFLAGS.gcc+=   -mno-align-long-strings
-.endif
 
 CFLAGS.clang+=	-Oz ${CLANG_OPT_SMALL}
 
Index: head/stand/i386/isoboot/Makefile
===================================================================
--- head/stand/i386/isoboot/Makefile
+++ head/stand/i386/isoboot/Makefile
@@ -32,9 +32,6 @@
 	-Winline -Wno-pointer-sign
 
 CFLAGS.gcc+=	--param max-inline-insns-single=100
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} <= 40201
-CFLAGS.gcc+=	-Wno-uninitialized
-.endif
 CFLAGS.clang+=  -Oz ${CLANG_OPT_SMALL}
 
 LD_FLAGS+=${LD_FLAGS_BIN}
Index: head/stand/libsa/Makefile
===================================================================
--- head/stand/libsa/Makefile
+++ head/stand/libsa/Makefile
@@ -46,11 +46,7 @@
 # Do not generate movt/movw, because the relocation fixup for them does not
 # translate to the -Bsymbolic -pie format required by self_reloc() in loader(8).
 # Also, the fpu is not available in a standalone environment.
-.if ${COMPILER_VERSION} < 30800
-CFLAGS.clang+=	-mllvm -arm-use-movt=0
-.else
 CFLAGS.clang+=	-mno-movt
-.endif
 CFLAGS.clang+=	-mfpu=none
 
 .PATH: ${SRCTOP}/contrib/llvm-project/compiler-rt/lib/builtins/arm/
Index: head/sys/conf/Makefile.arm
===================================================================
--- head/sys/conf/Makefile.arm
+++ head/sys/conf/Makefile.arm
@@ -44,10 +44,6 @@
 
 .if !empty(DDB_ENABLED)
 CFLAGS += -funwind-tables
-.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 30500
-# clang < 3.5.0 requires us to tell it to emit assembly with unwind information
-CFLAGS += -mllvm -arm-enable-ehabi
-.endif
 .endif
 
 # "makeoptions KERNVIRTADDR=" is now optional, supply the default value.
Index: head/sys/conf/Makefile.powerpc
===================================================================
--- head/sys/conf/Makefile.powerpc
+++ head/sys/conf/Makefile.powerpc
@@ -51,7 +51,7 @@
         -Wno-error=incompatible-pointer-types-discards-qualifiers \
         -Wno-error=non-literal-null-conversion \
         -Wno-error=enum-conversion
-.elif "${COMPILER_TYPE}" == "gcc" && ${COMPILER_VERSION} >= 50200
+.elif "${COMPILER_TYPE}" == "gcc"
 DPAAWARNFLAGS += \
 	-Wno-error=redundant-decls \
 	-Wno-error=int-in-bool-context
Index: head/sys/conf/kern.mk
===================================================================
--- head/sys/conf/kern.mk
+++ head/sys/conf/kern.mk
@@ -31,19 +31,14 @@
 CWARNEXTRA?=	-Wno-error-tautological-compare -Wno-error-empty-body \
 		-Wno-error-parentheses-equality -Wno-error-unused-function \
 		-Wno-error-pointer-sign
-.if ${COMPILER_VERSION} >= 30700
 CWARNEXTRA+=	-Wno-error-shift-negative-value
-.endif
-.if ${COMPILER_VERSION} >= 40000
 CWARNEXTRA+=	-Wno-address-of-packed-member
-.endif
 .if ${COMPILER_VERSION} >= 100000
 NO_WMISLEADING_INDENTATION=	-Wno-misleading-indentation
 .endif
-.endif
+.endif	# clang
 
 .if ${COMPILER_TYPE} == "gcc"
-.if ${COMPILER_VERSION} >= 40800
 # Catch-all for all the things that are in our tree, but for which we're
 # not yet ready for this compiler.
 NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable
@@ -55,15 +50,13 @@
 		-Wno-error=enum-compare				\
 		-Wno-error=inline				\
 		-Wno-error=maybe-uninitialized			\
+		-Wno-error=misleading-indentation		\
+		-Wno-error=nonnull-compare			\
 		-Wno-error=overflow				\
 		-Wno-error=sequence-point			\
-		-Wno-unused-but-set-variable
-.if ${COMPILER_VERSION} >= 60100
-CWARNEXTRA+=	-Wno-error=misleading-indentation		\
-		-Wno-error=nonnull-compare			\
 		-Wno-error=shift-overflow			\
-		-Wno-error=tautological-compare
-.endif
+		-Wno-error=tautological-compare			\
+		-Wno-unused-but-set-variable
 .if ${COMPILER_VERSION} >= 70100
 CWARNEXTRA+=	-Wno-error=stringop-overflow
 .endif
@@ -76,15 +69,7 @@
 .if ${COMPILER_VERSION} >= 90100
 CWARNEXTRA+=	-Wno-address-of-packed-member
 .endif
-.else
-# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars.
-CWARNEXTRA?=	-Wno-uninitialized
-# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for
-# the few files that are already known to generate cast-qual warnings.
-NO_WCAST_QUAL= -Wno-cast-qual
-NO_WNONNULL=	-Wno-nonnull
-.endif
-.endif
+.endif	# gcc
 
 # This warning is utter nonsense
 CWARNFLAGS+=	-Wno-format-zero-length
@@ -93,7 +78,7 @@
 # to be disabled.  WARNING: format checking is disabled in this case.
 .if ${MK_FORMAT_EXTENSIONS} == "no"
 FORMAT_EXTENSIONS=	-Wno-format
-.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
+.elif ${COMPILER_TYPE} == "clang"
 FORMAT_EXTENSIONS=	-D__printf__=__freebsd_kprintf__
 .else
 FORMAT_EXTENSIONS=	-fformat-extensions
@@ -201,12 +186,7 @@
 # DDB happy. ELFv2, if available, has some other efficiency benefits.
 #
 .if ${MACHINE_ARCH} == "powerpc64"
-.if ${COMPILER_VERSION} >= 40900
-CFLAGS.gcc+=	-mabi=elfv2
-.else
-CFLAGS.gcc+=	-mcall-aixdesc
-.endif
-CFLAGS.clang+=	-mabi=elfv2
+CFLAGS+=	-mabi=elfv2
 .endif
 
 #
Index: head/sys/conf/kern.post.mk
===================================================================
--- head/sys/conf/kern.post.mk
+++ head/sys/conf/kern.post.mk
@@ -345,10 +345,7 @@
 
 .depend: .PRECIOUS ${SRCS}
 
-.if ${COMPILER_TYPE} == "clang" || \
-    (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60000)
 _MAP_DEBUG_PREFIX= yes
-.endif
 
 _ILINKS= machine
 .if ${MACHINE} != ${MACHINE_CPUARCH} && ${MACHINE} != "arm64"
Index: head/sys/conf/kern.pre.mk
===================================================================
--- head/sys/conf/kern.pre.mk
+++ head/sys/conf/kern.pre.mk
@@ -93,11 +93,7 @@
 .if defined(CFLAGS_ARCH_PARAMS)
 CFLAGS.gcc+=${CFLAGS_ARCH_PARAMS}
 .endif
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} < 50000
-WERROR?=	-Wno-error
-.else
 WERROR?=	-Werror
-.endif
 # The following should be removed no earlier than LLVM11 being imported into the
 # tree, to ensure we don't regress the build.  LLVM11 and GCC10 will switch the
 # default over to -fno-common, making this redundant.
Index: head/sys/conf/kmod.mk
===================================================================
--- head/sys/conf/kmod.mk
+++ head/sys/conf/kmod.mk
@@ -88,11 +88,7 @@
 .if !empty(CFLAGS:M-O[23s]) && empty(CFLAGS:M-fno-strict-aliasing)
 CFLAGS+=	-fno-strict-aliasing
 .endif
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} < 50000
-WERROR?=	-Wno-error
-.else
 WERROR?=	-Werror
-.endif
 
 LINUXKPI_GENSRCS+= \
 	bus_if.h \
@@ -160,11 +156,7 @@
 # Temporary workaround for PR 196407, which contains the fascinating details.
 # Don't allow clang to use fpu instructions or registers in kernel modules.
 .if ${MACHINE_CPUARCH} == arm
-.if ${COMPILER_VERSION} < 30800
-CFLAGS.clang+=	-mllvm -arm-use-movt=0
-.else
 CFLAGS.clang+=	-mno-movt
-.endif
 CFLAGS.clang+=	-mfpu=none
 CFLAGS+=	-funwind-tables
 .endif
@@ -283,10 +275,7 @@
 	${OBJCOPY} --strip-debug ${.TARGET}
 .endif
 
-.if ${COMPILER_TYPE} == "clang" || \
-    (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60000)
 _MAP_DEBUG_PREFIX= yes
-.endif
 
 _ILINKS=machine
 .if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"
Index: head/sys/modules/Makefile
===================================================================
--- head/sys/modules/Makefile
+++ head/sys/modules/Makefile
@@ -620,9 +620,7 @@
 _aacraid=	aacraid
 _acpi=		acpi
 .if ${MK_CRYPT} != "no" || defined(ALL_MODULES)
-.if ${COMPILER_TYPE} != "gcc" || ${COMPILER_VERSION} > 40201
 _aesni=		aesni
-.endif
 .endif
 _amd_ecc_inject=amd_ecc_inject
 _amdsbwd=	amdsbwd
Index: head/usr.sbin/acpi/acpidb/Makefile
===================================================================
--- head/usr.sbin/acpi/acpidb/Makefile
+++ head/usr.sbin/acpi/acpidb/Makefile
@@ -87,6 +87,6 @@
 # integer to pointer, which is a GNU extension.
 #
 # Turn off the warning, because this is in contributed code.
-.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 60000
+.if ${COMPILER_TYPE} == "clang"
 CWARNFLAGS+=	-Wno-null-pointer-arithmetic
 .endif
Index: head/usr.sbin/trpt/Makefile
===================================================================
--- head/usr.sbin/trpt/Makefile
+++ head/usr.sbin/trpt/Makefile
@@ -8,18 +8,12 @@
 BINGRP=	kmem
 BINMODE= 2555
 
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} < 50000
-WARNS?=	4
-.endif
-
 .if ${MK_INET6_SUPPORT} != "no"
 CFLAGS+= -DINET6
 .endif
 
 .include <bsd.prog.mk>
 
-.if ${COMPILER_TYPE} != "gcc" || ${COMPILER_VERSION} >= 50000
 # Several included system headers tickle this warning in ways that are
 # difficult to work around in this program.
 CFLAGS+= -Wno-missing-variable-declarations
-.endif
Index: head/usr.sbin/zic/zic/Makefile
===================================================================
--- head/usr.sbin/zic/zic/Makefile
+++ head/usr.sbin/zic/zic/Makefile
@@ -15,7 +15,7 @@
 
 WARNS?=	2
 
-.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 50300
+.if ${COMPILER_TYPE} == "gcc"
 CWARNFLAGS+=	-Wno-error=strict-overflow
 .endif