RISC-V: Add dynamic LMUL compile option

We are going to support dynamic LMUL support.

gcc/ChangeLog:

	* config/riscv/riscv-opts.h (enum riscv_autovec_lmul_enum): Add
	dynamic enum.
	* config/riscv/riscv.opt: Add dynamic compile option.

2 files changed, 6 insertions, 1 deletions

diff --git a/gcc/config/riscv/riscv-opts.h b/gcc/config/riscv/riscv-opts.h
index 5ed69ab..79e0f12 100644
--- a/gcc/config/riscv/riscv-opts.h
+++ b/gcc/config/riscv/riscv-opts.h
@@ -79,7 +79,9 @@ enum riscv_autovec_lmul_enum {
   RVV_M1 = 1,
   RVV_M2 = 2,
   RVV_M4 = 4,
-  RVV_M8 = 8
+  RVV_M8 = 8,
+  /* For dynamic LMUL, we compare COST start with LMUL8.  */
+  RVV_DYNAMIC = RVV_M8
 };
 
 enum riscv_multilib_select_kind {
diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt
index d2407c3..eca0dda 100644
--- a/gcc/config/riscv/riscv.opt
+++ b/gcc/config/riscv/riscv.opt
@@ -311,6 +311,9 @@ Enum(riscv_autovec_lmul) String(m4) Value(RVV_M4)
 EnumValue
 Enum(riscv_autovec_lmul) String(m8) Value(RVV_M8)
 
+EnumValue
+Enum(riscv_autovec_lmul) String(dynamic) Value(RVV_DYNAMIC)
+
 -param=riscv-autovec-lmul=
 Target RejectNegative Joined Enum(riscv_autovec_lmul) Var(riscv_autovec_lmul) Init(RVV_M1)
 -param=riscv-autovec-lmul=<string>	Set the RVV LMUL of auto-vectorization in the RISC-V port.