arcv: Make -mtune=arc-v-rmx-100-series a default for ARC-V

We have 4 -mtune values for ARC-V targets:

1. arc-v-rmx-100-series
2. arc-v-rmx-500-series
3. arc-v-rhx-100-series
4. arc-v-rpx-100-series

When all of them are mentioned in a multilib configuration file
(t-arcv for ARC-V) and arc-v-rmx-100-series is a default -mtune
value (-with-tune= configuration option for GCC), then GCC cannot
build with default target options (like gcc app.c -o app).

To fix this we had to use -with-tune=rocket. However, with such
approach we have to pass -mtune for a particular ARC-V
target manually and not rely on RMX-100 as a default target.

This patch removes -mtune from t-arcv for all RMX-100 targets
and sets -with-tune=arc-v-rmx-100-series if it's not set
explicitly (it corresponds to -with-tune=default). This allows
using -mtune=arc-v-rmx-100-series as default without passing
extra configuration options to GCC build scripts and fixes that
bug with default target options.

Signed-off-by: Yuriy Kolerov <[email protected]>

Author: kolerov

gcc/config.gcc

@@ -4910,6 +4910,18 @@ case "${target}" in
 				exit 1
 			esac
 		fi
+
+		# Handle --with-tune.
+		if test "x${with_tune}" = xdefault; then
+			case ${target} in
+			*-snps-*)
+				# Use a default mtune for Synopsys ARC-V.
+				with_tune=arc-v-rmx-100-series
+				;;
+			*)
+				;;
+			esac
+		fi
 		;;
 
 	mips*-*-*)

gcc/config/riscv/t-arcv

@@ -59,41 +59,41 @@ MULTILIB_DIRNAMES   += $(arcv_march_variants)
 MULTILIB_OPTIONS    += mabi=ilp32e/mabi=ilp32/mabi=ilp32f/mabi=ilp32d/mabi=lp64/mabi=lp64d
 MULTILIB_DIRNAMES   +=      ilp32e      ilp32      ilp32f      ilp32d      lp64      lp64d
 
-MULTILIB_OPTIONS    += mtune=arc-v-rmx-100-series/mtune=arc-v-rmx-500-series/mtune=arc-v-rhx-100-series/mtune=arc-v-rpx-100-series
-MULTILIB_DIRNAMES   +=       rmx100                     rmx500                     rhx100                     rpx100
+MULTILIB_OPTIONS    += mtune=arc-v-rmx-500-series/mtune=arc-v-rhx-100-series/mtune=arc-v-rpx-100-series
+MULTILIB_DIRNAMES   +=       rmx500                     rhx100                     rpx100
 
 MULTILIB_OPTIONS    += mcmodel=medany
 MULTILIB_DIRNAMES   +=         medany
 
 # Configurations for RMX-100 mini
-MULTILIB_REQUIRED   += march=rv32e/mabi=ilp32e/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32em/mabi=ilp32e/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ea/mabi=ilp32e/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ema/mabi=ilp32e/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32emac_zcb_zba_zbb_zbs_zfinx_zdinx/mabi=ilp32e/mtune=arc-v-rmx-100-series
+MULTILIB_REQUIRED   += march=rv32e/mabi=ilp32e
+MULTILIB_REQUIRED   += march=rv32em/mabi=ilp32e
+MULTILIB_REQUIRED   += march=rv32ea/mabi=ilp32e
+MULTILIB_REQUIRED   += march=rv32ema/mabi=ilp32e
+MULTILIB_REQUIRED   += march=rv32emac_zcb_zba_zbb_zbs_zfinx_zdinx/mabi=ilp32e
 
 # Configurations for RMX-100 - general
-MULTILIB_REQUIRED   += march=rv32i/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ic/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32im/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ia/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ima/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32iac/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32imac/mabi=ilp32/mtune=arc-v-rmx-100-series
+MULTILIB_REQUIRED   += march=rv32i/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32ic/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32im/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32ia/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32ima/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32iac/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32imac/mabi=ilp32
 
 # Configurations for RMX-100 - optimized
-MULTILIB_REQUIRED   += march=rv32ic_zcb_zba_zbb_zbs/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32imc_zcb_zba_zbb_zbs/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32imac_zcb_zba_zbb_zbs/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32imac_zcb_zba_zbb_zbs_zfinx/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32imac_zcb_zba_zbb_zbs_zfinx_zdinx/mabi=ilp32/mtune=arc-v-rmx-100-series
+MULTILIB_REQUIRED   += march=rv32ic_zcb_zba_zbb_zbs/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32imc_zcb_zba_zbb_zbs/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32imac_zcb_zba_zbb_zbs/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32imac_zcb_zba_zbb_zbs_zfinx/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32imac_zcb_zba_zbb_zbs_zfinx_zdinx/mabi=ilp32
 
 # Configurations for RMX-100 - optimized (without C and Zc*)
-MULTILIB_REQUIRED   += march=rv32i_zba_zbb_zbs/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32im_zba_zbb_zbs/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ima_zba_zbb_zbs/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ima_zba_zbb_zbs_zfinx/mabi=ilp32/mtune=arc-v-rmx-100-series
-MULTILIB_REQUIRED   += march=rv32ima_zba_zbb_zbs_zfinx_zdinx/mabi=ilp32/mtune=arc-v-rmx-100-series
+MULTILIB_REQUIRED   += march=rv32i_zba_zbb_zbs/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32im_zba_zbb_zbs/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32ima_zba_zbb_zbs/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32ima_zba_zbb_zbs_zfinx/mabi=ilp32
+MULTILIB_REQUIRED   += march=rv32ima_zba_zbb_zbs_zfinx_zdinx/mabi=ilp32
 
 # Configurations for RMX-500 - general
 MULTILIB_REQUIRED   += march=rv32i/mabi=ilp32/mtune=arc-v-rmx-500-series