From 8c06a8dc8fde05e8c6619a51977862c1062756ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Tue, 4 Aug 2026 12:16:20 +0200
Subject: [PATCH] compiler: add loongarch(32,64)_preserve_none calling
 convention support

---
 lib/std/Target.zig     | 2 ++
 lib/std/lang.zig       | 2 ++
 src/Zcu.zig            | 2 ++
 src/codegen/c/type.zig | 2 ++
 src/codegen/llvm.zig   | 2 ++
 src/link/Dwarf.zig     | 3 +++
 test/c_abi/cfuncs.c    | 2 +-
 test/c_abi/main.zig    | 3 +++
 8 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/std/Target.zig b/lib/std/Target.zig
index ef1c1e5a21b06d1f86566d21ad57ed848ee3a472..6ced31ac891a5976fc17259336c9d9fe7996ac3f 100644
--- a/lib/std/Target.zig
+++ b/lib/std/Target.zig
@@ -1961,9 +1961,11 @@ pub const Cpu = struct {
                 => &.{.lanai},
 
                 .loongarch64_lp64,
+                .loongarch64_preserve_none,
                 => &.{.loongarch64},
 
                 .loongarch32_ilp32,
+                .loongarch32_preserve_none,
                 => &.{.loongarch32},
 
                 .m68k_sysv,
diff --git a/lib/std/lang.zig b/lib/std/lang.zig
index 5ae5c46dee2995dd7a66f46cc35fb14b47d1e953..ef98f3ce8f3d61778ec9c5fe7ead8234a6bb9b72 100644
--- a/lib/std/lang.zig
+++ b/lib/std/lang.zig
@@ -322,9 +322,11 @@ pub const CallingConvention = union(enum(u8)) {
 
     /// The standard `loongarch64` calling convention.
     loongarch64_lp64: CommonOptions,
+    loongarch64_preserve_none: CommonOptions,
 
     /// The standard `loongarch32` calling convention.
     loongarch32_ilp32: CommonOptions,
+    loongarch32_preserve_none: CommonOptions,
 
     // Calling conventions for the `m68k` architecture.
     m68k_sysv: CommonOptions,
diff --git a/src/Zcu.zig b/src/Zcu.zig
index 0f2c93bb92336704727aad07a387ebe8c9812af4..4a8936e3961f109c07f59c38583bcc574633c7a2 100644
--- a/src/Zcu.zig
+++ b/src/Zcu.zig
@@ -4711,6 +4711,8 @@ pub fn callconvSupported(zcu: *Zcu, cc: std.lang.CallingConvention) union(enum)
                 .avr_interrupt,
                 .avr_signal,
                 .ez80_tiflags,
+                .loongarch32_preserve_none,
+                .loongarch64_preserve_none,
                 .naked,
                 => true, // incoming stack alignment supported
 
diff --git a/src/codegen/c/type.zig b/src/codegen/c/type.zig
index 4b0abd42ccba9bd00cbb5804b5e8e8ed43b0f221..c77467de9c8534dbbeabb9bd01a7e72db310c90c 100644
--- a/src/codegen/c/type.zig
+++ b/src/codegen/c/type.zig
@@ -142,6 +142,8 @@ pub const CType = union(enum) {
 
                 .x86_64_preserve_none,
                 .aarch64_preserve_none,
+                .loongarch32_preserve_none,
+                .loongarch64_preserve_none,
                 => .preserve_none,
 
                 .aarch64_vfabi => .aarch64_vector_pcs,
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 2b2edd07e9551815ced40e2287be6b91c3806f13..1a7c27123dba856e405d3caf08bcfe30ac770839 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -4341,6 +4341,8 @@ pub fn toLlvmCallConvTag(cc_tag: std.lang.CallingConvention.Tag, target: *const
         .amdgcn_cs => .amdgpu_cs,
         .nvptx_device => .ptx_device,
         .nvptx_kernel => .ptx_kernel,
+        .loongarch32_preserve_none => .preserve_nonecc,
+        .loongarch64_preserve_none => .preserve_nonecc,
 
         // Calling conventions which LLVM uses function attributes for.
         .riscv64_interrupt,
diff --git a/src/link/Dwarf.zig b/src/link/Dwarf.zig
index a119e3d43062f7ddacd0c4f3fdcfcc3e4ec9dd18..fab66811a051ae024a309bc1d210025017054844 100644
--- a/src/link/Dwarf.zig
+++ b/src/link/Dwarf.zig
@@ -4189,6 +4189,9 @@ fn updateConstInner(dwarf: *Dwarf, pt: Zcu.PerThread, debug_const_index: link.Co
                     .riscv32_ilp32_v,
                     => .LLVM_RISCVVectorCall,
 
+                    .loongarch32_preserve_none => .LLVM_PreserveNone,
+                    .loongarch64_preserve_none => .LLVM_PreserveNone,
+
                     .m68k_rtd => .LLVM_M68kRTD,
 
                     .sh_renesas => .GNU_renesas_sh,
diff --git a/test/c_abi/cfuncs.c b/test/c_abi/cfuncs.c
index 327bc04ceb34148541b994bb894f04bea85bf210..cce4f0d77497f2c6579fcd25eb0a6028dc2b1064 100644
--- a/test/c_abi/cfuncs.c
+++ b/test/c_abi/cfuncs.c
@@ -16624,7 +16624,7 @@ struct ByRef __attribute__((sysv_abi)) c_explict_sys_v(struct ByRef in) {
 }
 #endif
 
-#if defined __x86_64__ || defined __aarch64__
+#if defined __x86_64__ || defined __aarch64__ || defined __loongarch__
 int __attribute__((preserve_none)) c_preserve_none(int x) {
     return x + 1;
 }
diff --git a/test/c_abi/main.zig b/test/c_abi/main.zig
index a481a015117276e8abf7c4393f6d85cf60dd20fb..e7b98a181148e9aecfe3aeb775e8e3f62c15f036 100644
--- a/test/c_abi/main.zig
+++ b/test/c_abi/main.zig
@@ -18045,6 +18045,9 @@ const preserve_none_cc: ?std.lang.CallingConvention = if (builtin.zig_backend !=
 else switch (builtin.cpu.arch) {
     .x86_64 => .{ .x86_64_preserve_none = .{} },
     .aarch64, .aarch64_be => .{ .aarch64_preserve_none = .{} },
+    // Supported in LLVM but not yet wired up in Clang.
+    // .loongarch32 => .{ .loongarch32_preserve_none = .{} },
+    // .loongarch64 => .{ .loongarch64_preserve_none = .{} },
     else => null,
 };
 
-- 
2.54.0