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Compiler segfaults when using self hosted backend. #31979

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opened 2026年04月20日 11:27:58 +02:00 by ItsMeSamey · 2 comments

ItsMeSamey commented

2026年04月20日 11:27:58 +02:00

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Zig Version

0.16.0

Steps to Reproduce and Observed Behavior

constR15=packedstruct{_:void,r:u15,};fnnothing(v:u15)u15{returnv;}pubfnmain()void{_=R15{._={},.r=nothing(123),};}

zig build-exe -fno-llvm bug_repro.zig on x86_64-linux.6.19.11...6.19.11-gnu.2.43

Similar issue: #31837

Expected Behavior

No segfault

### Zig Version 0.16.0 ### Steps to Reproduce and Observed Behavior ```zig const R15 = packed struct { _: void, r: u15, }; fn nothing(v: u15) u15 { return v; } pub fn main() void { _ = R15{ ._ = {}, .r = nothing(123), }; } ``` `zig build-exe -fno-llvm bug_repro.zig` on x86_64-linux.6.19.11...6.19.11-gnu.2.43 Similar issue: https://codeberg.org/ziglang/zig/issues/31837 ### Expected Behavior No segfault

ItsMeSamey added the

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2026年04月20日 11:27:58 +02:00

nektro commented

2026年04月20日 12:02:11 +02:00

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stack trace

stack trace:
/home/meghan/src/zigfork/lib/std/debug.zig:420:14: 0x1954509 in assert (std.zig)
 if (!ok) unreachable; // assertion failure
 ^
/home/meghan/src/zigfork/lib/std/math.zig:1123:11: 0x1c88f80 in isPowerOfTwo__anon_89798 (std.zig)
 assert(int > 0);
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:174084:34: 0x3990707 in allocRegOrMemAdvanced (main.zig)
 if (std.math.isPowerOfTwo(abi_size) and abi_size <= @as(u32, max_abi_size: switch (ty.zigTypeTag(zcu)) {
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:174069:38: 0x3990eaa in allocRegOrMem (main.zig)
 return self.allocRegOrMemAdvanced(self.typeOfIndex(inst), inst, reg_ok);
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:179462:51: 0x4c6d86d in airBitCast (main.zig)
 const dst_mcv = try self.allocRegOrMem(inst, true);
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:67357:42: 0x4ccac32 in genBody (main.zig)
 .bitcast => try cg.airBitCast(inst),
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:176545:21: 0x4c72a76 in lowerBlock (main.zig)
 try self.genBody(body);
 ^ration
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:67361:34: 0x4ccae0c in genBody (main.zig)
 try cg.lowerBlock(inst, block.body);
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:2271:19: 0x4c1ba3f in genMainBody (main.zig)
 try cg.genBody(main_body[air_arg_count..]);
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:2067:29: 0x4c00be1 in gen (main.zig)
 try self.genMainBody(zir, func_zir_inst, comptime_args, air_arg_count);
 ^
/home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:985:17: 0x4bf84a4 in generate (main.zig)
 function.gen(&file.zir.?, func_zir.inst, func.comptime_args, call_info.air_arg_count) catch |err| switch (err) {
 ^
/home/meghan/src/zigfork/src/codegen.zig:163:45: 0x4b03a49 in generateFunction (main.zig)
 const mir = try CodeGen.generate(lf, pt, src_loc, func_index, air, liveness);
 ^
/home/meghan/src/zigfork/src/Zcu/PerThread.zig:4613:36: 0x4ad55d9 in runCodegenInner (main.zig)
 return codegen.generateFunction(lf, pt, zcu.navSrcLoc(nav), func_index, air, &liveness) catch |err| switch (err) {
 ^
/home/meghan/src/zigfork/src/Zcu/PerThread.zig:4489:43: 0x4ad3215 in runCodegen (main.zig)
 const codegen_result = runCodegenInner(pt, func_index, air);
 ^
/home/meghan/src/zigfork/src/Zcu.zig:5381:29: 0x4ad2f20 in workerCodegenOwnedAir (main.zig)
 return pt.runCodegen(func_index, &air);
 ^

<details> <summary> stack trace </summary> ``` stack trace: /home/meghan/src/zigfork/lib/std/debug.zig:420:14: 0x1954509 in assert (std.zig) if (!ok) unreachable; // assertion failure ^ /home/meghan/src/zigfork/lib/std/math.zig:1123:11: 0x1c88f80 in isPowerOfTwo__anon_89798 (std.zig) assert(int > 0); ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:174084:34: 0x3990707 in allocRegOrMemAdvanced (main.zig) if (std.math.isPowerOfTwo(abi_size) and abi_size <= @as(u32, max_abi_size: switch (ty.zigTypeTag(zcu)) { ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:174069:38: 0x3990eaa in allocRegOrMem (main.zig) return self.allocRegOrMemAdvanced(self.typeOfIndex(inst), inst, reg_ok); ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:179462:51: 0x4c6d86d in airBitCast (main.zig) const dst_mcv = try self.allocRegOrMem(inst, true); ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:67357:42: 0x4ccac32 in genBody (main.zig) .bitcast => try cg.airBitCast(inst), ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:176545:21: 0x4c72a76 in lowerBlock (main.zig) try self.genBody(body); ^ration /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:67361:34: 0x4ccae0c in genBody (main.zig) try cg.lowerBlock(inst, block.body); ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:2271:19: 0x4c1ba3f in genMainBody (main.zig) try cg.genBody(main_body[air_arg_count..]); ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:2067:29: 0x4c00be1 in gen (main.zig) try self.genMainBody(zir, func_zir_inst, comptime_args, air_arg_count); ^ /home/meghan/src/zigfork/src/codegen/x86_64/CodeGen.zig:985:17: 0x4bf84a4 in generate (main.zig) function.gen(&file.zir.?, func_zir.inst, func.comptime_args, call_info.air_arg_count) catch |err| switch (err) { ^ /home/meghan/src/zigfork/src/codegen.zig:163:45: 0x4b03a49 in generateFunction (main.zig) const mir = try CodeGen.generate(lf, pt, src_loc, func_index, air, liveness); ^ /home/meghan/src/zigfork/src/Zcu/PerThread.zig:4613:36: 0x4ad55d9 in runCodegenInner (main.zig) return codegen.generateFunction(lf, pt, zcu.navSrcLoc(nav), func_index, air, &liveness) catch |err| switch (err) { ^ /home/meghan/src/zigfork/src/Zcu/PerThread.zig:4489:43: 0x4ad3215 in runCodegen (main.zig) const codegen_result = runCodegenInner(pt, func_index, air); ^ /home/meghan/src/zigfork/src/Zcu.zig:5381:29: 0x4ad2f20 in workerCodegenOwnedAir (main.zig) return pt.runCodegen(func_index, &air); ^ ``` </details>

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2026年04月20日 15:50:37 +02:00

linus commented

2026年04月20日 15:59:12 +02:00

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Looks like an exact duplicate of #31837 actually.

linus

2026年04月20日 15:59:13 +02:00

closed this issue
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