From c717b0d08df5a0d1ca94d718fd4d28d3334eed57 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Fri, 22 May 2026 21:11:09 +0200
Subject: [PATCH 1/2] std.Target: add spacemit_x100 and spacemit_a100 RISC-V
 CPU models

Backported from LLVM main branch.
---
 lib/std/Target/riscv.zig      | 97 +++++++++++++++++++++++++++++++++++
 tools/update_cpu_features.zig | 97 +++++++++++++++++++++++++++++++++++
 2 files changed, 194 insertions(+)

diff --git a/lib/std/Target/riscv.zig b/lib/std/Target/riscv.zig
index b745ac4bbe..c935a90490 100644
--- a/lib/std/Target/riscv.zig
+++ b/lib/std/Target/riscv.zig
@@ -3370,6 +3370,103 @@ pub const cpu = struct {
             .zvl1024b,
         }),
     };
+    pub const spacemit_a100: CpuModel = .{
+        .name = "spacemit_a100",
+        .llvm_name = null,
+        .features = featureSet(&[_]Feature{
+            .@"64bit",
+            .a,
+            .b,
+            .c,
+            .dlen_factor_2,
+            .i,
+            .m,
+            .optimized_nf2_segment_load_store,
+            .optimized_nf3_segment_load_store,
+            .optimized_nf4_segment_load_store,
+            .smepmp,
+            .smnpm,
+            .smstateen,
+            .ssccptr,
+            .sscofpmf,
+            .sscounterenw,
+            .ssnpm,
+            .sspm,
+            .sstc,
+            .sstvala,
+            .sstvecd,
+            .ssu64xl,
+            .supm,
+            .svade,
+            .svbare,
+            .svinval,
+            .svnapot,
+            .svpbmt,
+            .unaligned_scalar_mem,
+            .v,
+            .vxrm_pipeline_flush,
+            .za64rs,
+            .zawrs,
+            .zbc,
+            .zbkc,
+            .zcb,
+            .zcmop,
+            .zfa,
+            .zfh,
+            .zic64b,
+            .zicbom,
+            .zicbop,
+            .zicboz,
+            .ziccamoa,
+            .ziccif,
+            .zicclsm,
+            .ziccrse,
+            .zicntr,
+            .zicond,
+            .zifencei,
+            .zihintntl,
+            .zihintpause,
+            .zihpm,
+            .zimop,
+            .zkt,
+            .zvbb,
+            .zvfbfwma,
+            .zvfh,
+            .zvkng,
+            .zvknha,
+            .zvksc,
+            .zvksg,
+            .zvl1024b,
+        }),
+    };
+    pub const spacemit_x100: CpuModel = .{
+        .name = "spacemit_x100",
+        .llvm_name = null,
+        .features = featureSet(&[_]Feature{
+            .dlen_factor_2,
+            .optimized_nf2_segment_load_store,
+            .optimized_nf3_segment_load_store,
+            .optimized_nf4_segment_load_store,
+            .rva23s64,
+            .smepmp,
+            .smnpm,
+            .smstateen,
+            .sspm,
+            .unaligned_scalar_mem,
+            .vxrm_pipeline_flush,
+            .xsmtvdot,
+            .zbc,
+            .zbkc,
+            .zfh,
+            .zvfbfwma,
+            .zvfh,
+            .zvkng,
+            .zvknha,
+            .zvksc,
+            .zvksg,
+            .zvl256b,
+        }),
+    };
     pub const spacemit_x60: CpuModel = .{
         .name = "spacemit_x60",
         .llvm_name = "spacemit-x60",
diff --git a/tools/update_cpu_features.zig b/tools/update_cpu_features.zig
index 162a48bace..2b450853e1 100644
--- a/tools/update_cpu_features.zig
+++ b/tools/update_cpu_features.zig
@@ -1548,6 +1548,103 @@ const targets = [_]ArchTarget{
                 .zig_name = "baseline_rv64",
                 .features = &.{ "64bit", "a", "c", "d", "f", "i", "m" },
             },
+            .{
+                .llvm_name = null,
+                .zig_name = "spacemit_a100",
+                .features = &.{
+                    "64bit",
+                    "a",
+                    "b",
+                    "c",
+                    "dlen_factor_2",
+                    "i",
+                    "m",
+                    "optimized_nf2_segment_load_store",
+                    "optimized_nf3_segment_load_store",
+                    "optimized_nf4_segment_load_store",
+                    "smepmp",
+                    "smnpm",
+                    "smstateen",
+                    "ssccptr",
+                    "sscofpmf",
+                    "sscounterenw",
+                    "ssnpm",
+                    "sspm",
+                    "sstc",
+                    "sstvala",
+                    "sstvecd",
+                    "ssu64xl",
+                    "supm",
+                    "svade",
+                    "svbare",
+                    "svinval",
+                    "svnapot",
+                    "svpbmt",
+                    "unaligned_scalar_mem",
+                    "v",
+                    "vxrm_pipeline_flush",
+                    "za64rs",
+                    "zawrs",
+                    "zbc",
+                    "zbkc",
+                    "zcb",
+                    "zcmop",
+                    "zfa",
+                    "zfh",
+                    "zic64b",
+                    "zicbom",
+                    "zicbop",
+                    "zicboz",
+                    "ziccamoa",
+                    "ziccif",
+                    "zicclsm",
+                    "ziccrse",
+                    "zicntr",
+                    "zicond",
+                    "zifencei",
+                    "zihintntl",
+                    "zihintpause",
+                    "zihpm",
+                    "zimop",
+                    "zkt",
+                    "zvbb",
+                    "zvfbfwma",
+                    "zvfh",
+                    "zvkng",
+                    "zvknha",
+                    "zvksc",
+                    "zvksg",
+                    "zvl1024b",
+                },
+            },
+            .{
+                .llvm_name = null,
+                .zig_name = "spacemit_x100",
+                .features = &.{
+                    "dlen_factor_2",
+                    "optimized_nf2_segment_load_store",
+                    "optimized_nf3_segment_load_store",
+                    "optimized_nf4_segment_load_store",
+                    "rva23s64",
+                    "smepmp",
+                    "smnpm",
+                    "smstateen",
+                    "sspm",
+                    "unaligned_scalar_mem",
+                    "vxrm_pipeline_flush",
+                    "xsmtvdot",
+                    "zbc",
+                    "zbkc",
+                    "zfh",
+                    "zvfbfwma",
+                    "zvfh",
+                    "zvkng",
+                    "zvknha",
+                    "zvksc",
+                    "zvksg",
+                    "zvl256b",
+                },
+            },
         },
     },
     .{

From d70b56429c4f518c92f6419ce369d6098650ff96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Fri, 22 May 2026 21:12:28 +0200
Subject: [PATCH 2/2] std.zig.system.linux: add detection for more RISC-V CPU
 models

---
 lib/std/zig/system/linux.zig | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/std/zig/system/linux.zig b/lib/std/zig/system/linux.zig
index 60f4d7bfec..82f13bc7a4 100644
--- a/lib/std/zig/system/linux.zig
+++ b/lib/std/zig/system/linux.zig
@@ -70,12 +70,16 @@ const RiscvCpuinfoImpl = struct {
     model: ?*const Target.Cpu.Model = null,
 
     const cpu_names = .{
+        .{ "andestech,ax45mp", &Target.riscv.cpu.andes_ax45 },
+        .{ "sifive,p550", &Target.riscv.cpu.sifive_p550 },
         .{ "sifive,u54", &Target.riscv.cpu.sifive_u54 },
         .{ "sifive,u54-mc", &Target.riscv.cpu.sifive_u54 },
         .{ "sifive,u7", &Target.riscv.cpu.sifive_7_series },
         .{ "sifive,u74", &Target.riscv.cpu.sifive_u74 },
         .{ "sifive,u74-mc", &Target.riscv.cpu.sifive_u74 },
+        .{ "sifive,x280", &Target.riscv.cpu.sifive_x280 },
         .{ "spacemit,x60", &Target.riscv.cpu.spacemit_x60 },
+        .{ "spacemit,x100", &Target.riscv.cpu.spacemit_x100 },
     };
 
     fn line_hook(self: *RiscvCpuinfoImpl, key: []const u8, value: []const u8) !bool {