[toolchain,apps] Bump LLVM to v18.1.6

Makefile

@@ -120,7 +120,7 @@ toolchain-llvm-rt: Makefile toolchain-llvm-main toolchain-llvm-newlib
 	-DLLVM_CONFIG_PATH=$(LLVM_INSTALL_DIR)/bin/llvm-config
 	cd $(ROOT_DIR)/toolchain/riscv-llvm/compiler-rt && \
 	$(CMAKE) --build build --target install && \
-	ln -s $(LLVM_INSTALL_DIR)/lib/linux $(LLVM_INSTALL_DIR)/lib/clang/16/lib
+	ln -s $(LLVM_INSTALL_DIR)/lib/linux $(LLVM_INSTALL_DIR)/lib/clang/18/lib
 
 # Spike
 .PHONY: riscv-isa-sim riscv-isa-sim-mod

apps/common/runtime.mk

@@ -85,7 +85,7 @@ DEFINES += $(ENV_DEFINES) $(MAKE_DEFINES)
 RISCV_WARNINGS += -Wunused-variable -Wall -Wextra -Wno-unused-command-line-argument # -Werror
 
 # LLVM Flags
-LLVM_FLAGS     ?= -march=rv64gcv_zfh_zvfh0p1 -menable-experimental-extensions -mabi=$(RISCV_ABI) -mno-relax -fuse-ld=lld
+LLVM_FLAGS     ?= -march=rv64gcv_zfh -mabi=$(RISCV_ABI) -mno-relax -fuse-ld=lld
 LLVM_V_FLAGS   ?= -fno-vectorize -mllvm -scalable-vectorization=off -mllvm -riscv-v-vector-bits-min=0 -Xclang -target-feature -Xclang +no-optimized-zero-stride-load
 RISCV_FLAGS    ?= $(LLVM_FLAGS) $(LLVM_V_FLAGS) -mcmodel=medany -I$(CURDIR)/common -std=gnu99 -O3 -ffast-math -fno-common -fno-builtin-printf $(DEFINES) $(RISCV_WARNINGS)
 RISCV_CCFLAGS  ?= $(RISCV_FLAGS) -ffunction-sections -fdata-sections