[PATCH] RISC-V: Tie MUL and DIV masks to the M extension

[Dimitar Dimitrov]

When configuring GCC for RV32EC with:
  ./configure                                     \
      --target=riscv32-none-elf                   \
      --with-multilib-generator="rv32ec-ilp32e--" \
      --with-abi=ilp32e                           \
      --with-arch=rv32ec

Then the build fails because division is erroneously left enabled:
   cc1: error: '-mdiv' requires '-march' to subsume the 'M' extension
   -fself-test: 8412281 pass(es) in 0.647173 seconds

Fix by tying both MUL and DIV option masks to the "M" standard extension
for integer multiplication and division.

Tested the above RV32EC-only toolchain using the GNU simulator:
                === gcc Summary ===

 # of expected passes            211621
 # of unexpected failures        3018
 # of expected failures          1061
 # of unresolved testcases       5651
 # of unsupported tests          18958

Ok for trunk?

gcc/ChangeLog:

        * common/config/riscv/riscv-common.cc: Tie both MUL and DIV to
        the M extension.

Signed-off-by: Dimitar Dimitrov <dimi...@dinux.eu>
---
 gcc/common/config/riscv/riscv-common.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/common/config/riscv/riscv-common.cc 
b/gcc/common/config/riscv/riscv-common.cc
index 60595a3e356..227bc3b89c0 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -1589,7 +1589,7 @@ struct riscv_ext_flag_table_t {
 static const riscv_ext_flag_table_t riscv_ext_flag_table[] =
 {
   RISCV_EXT_FLAG_ENTRY ("e", x_target_flags, MASK_RVE),
-  RISCV_EXT_FLAG_ENTRY ("m", x_target_flags, MASK_MUL),
+  RISCV_EXT_FLAG_ENTRY ("m", x_target_flags, MASK_MUL | MASK_DIV),
   RISCV_EXT_FLAG_ENTRY ("a", x_target_flags, MASK_ATOMIC),
   RISCV_EXT_FLAG_ENTRY ("f", x_target_flags, MASK_HARD_FLOAT),
   RISCV_EXT_FLAG_ENTRY ("d", x_target_flags, MASK_DOUBLE_FLOAT),
-- 
2.47.0