configure: probe RISC-V Vector extension

Makefile

@@ -91,7 +91,7 @@ ffbuild/.config: $(CONFIGURABLE_COMPONENTS)
 SUBDIR_VARS := CLEANFILES FFLIBS HOSTPROGS TESTPROGS TOOLS               \
                HEADERS ARCH_HEADERS BUILT_HEADERS SKIPHEADERS            \
                ARMV5TE-OBJS ARMV6-OBJS ARMV8-OBJS VFP-OBJS NEON-OBJS     \
-               ALTIVEC-OBJS VSX-OBJS MMX-OBJS X86ASM-OBJS                \
+               ALTIVEC-OBJS VSX-OBJS RVV-OBJS MMX-OBJS X86ASM-OBJS       \
                MIPSFPU-OBJS MIPSDSPR2-OBJS MIPSDSP-OBJS MSA-OBJS         \
                MMI-OBJS LSX-OBJS LASX-OBJS OBJS SLIBOBJS SHLIBOBJS       \
                STLIBOBJS HOSTOBJS TESTOBJS

configure

@@ -462,6 +462,7 @@ Optimization options (experts only):
   --disable-mmi            disable Loongson MMI optimizations
   --disable-lsx            disable Loongson LSX optimizations
   --disable-lasx           disable Loongson LASX optimizations
+  --disable-rvv            disable RISC-V Vector optimizations
   --disable-fast-unaligned consider unaligned accesses slow
 
 Developer options (useful when working on FFmpeg itself):
@@ -2126,6 +2127,10 @@ ARCH_EXT_LIST_PPC="
     vsx
 "
 
+ARCH_EXT_LIST_RISCV="
+    rvv
+"
+
 ARCH_EXT_LIST_X86="
     $ARCH_EXT_LIST_X86_SIMD
     cpunop
@@ -2135,6 +2140,7 @@ ARCH_EXT_LIST_X86="
 ARCH_EXT_LIST="
     $ARCH_EXT_LIST_ARM
     $ARCH_EXT_LIST_PPC
+    $ARCH_EXT_LIST_RISCV
     $ARCH_EXT_LIST_X86
     $ARCH_EXT_LIST_MIPS
     $ARCH_EXT_LIST_LOONGSON
@@ -2642,6 +2648,8 @@ ppc4xx_deps="ppc"
 vsx_deps="altivec"
 power8_deps="vsx"
 
+rvv_deps="riscv"
+
 loongson2_deps="mips"
 loongson3_deps="mips"
 mmi_deps_any="loongson2 loongson3"
@@ -6110,6 +6118,10 @@ elif enabled ppc; then
         check_cpp_condition power8 "altivec.h" "defined(_ARCH_PWR8)"
     fi
 
+elif enabled riscv; then
+
+    enabled rvv && check_inline_asm rvv '".option arch, +v\nvsetivli zero, 0, e8, m1, ta, ma"'
+
 elif enabled x86; then
 
     check_builtin rdtsc    intrin.h   "__rdtsc()"
@@ -7596,6 +7608,9 @@ if enabled loongarch; then
     echo "LSX enabled               ${lsx-no}"
     echo "LASX enabled              ${lasx-no}"
 fi
+if enabled riscv; then
+    echo "RISC-V Vector enabled     ${rvv-no}"
+fi
 echo "debug symbols             ${debug-no}"
 echo "strip symbols             ${stripping-no}"
 echo "optimize for size         ${small-no}"

ffbuild/arch.mak

@@ -15,5 +15,7 @@ OBJS-$(HAVE_LASX)      += $(LASX-OBJS)       $(LASX-OBJS-yes)
 OBJS-$(HAVE_ALTIVEC) += $(ALTIVEC-OBJS) $(ALTIVEC-OBJS-yes)
 OBJS-$(HAVE_VSX)     += $(VSX-OBJS) $(VSX-OBJS-yes)
 
+OBJS-$(HAVE_RVV)     += $(RVV-OBJS)     $(RVV-OBJS-yes)
+
 OBJS-$(HAVE_MMX)     += $(MMX-OBJS)     $(MMX-OBJS-yes)
 OBJS-$(HAVE_X86ASM)  += $(X86ASM-OBJS)  $(X86ASM-OBJS-yes)