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`zig build-exe` crash on x86_64 with soft-float enabled #31878

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opened 2026年04月15日 13:48:29 +02:00 by sagehane · 3 comments

sagehane commented

2026年04月15日 13:48:29 +02:00

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Zig Version

0.16.0-dev.3153+d6f43caad

Steps to Reproduce and Observed Behavior

Extracted from #31856 (comment)

Compile any Zig file (can be empty) with -mcpu=baseline+soft_float for x86_64 to be met with the following:

$ zig build-exe minimal.zig -target x86_64-linux -mcpu=baseline+soft_float
LLVM ERROR: Do not know how to soften the result of this operator!
Aborted (core dumped)
$ ] compiler_rt
└─ [2528/2528] Linking
 └─ LLVM Emit Object
[797] Semantic Analysis
└─ process.SpawnOptions

I tried versions dating back to 0.11.0 and consistently got a crash on all of them. It looks like 0.14.1 has the most useful error message out of the releases:

$ zig version
0.14.1
$ zig build-exe minimal.zig -target x86_64-linux -mcpu=baseline+soft_float
LLVM ERROR: Cannot select: 0x7fc9edf16950: i32 = X86ISD::CMP undef:i1, Constant:i1<0>, mulc3.zig:61:31 @[ mulxc3.zig:13:23 ]
 0x7fc9ee69b7f0: i1 = undef
 0x7fc9edd40240: i1 = Constant<0>
In function: __mulxc3
Aborted (core dumped) zig build-exe minimal.zig -target x86_64-linux -mcpu=baseline+soft_float

Expected Behavior

The compiler shouldn't crash.

### Zig Version 0.16.0-dev.3153+d6f43caad ### Steps to Reproduce and Observed Behavior Extracted from https://codeberg.org/ziglang/zig/issues/31856#issuecomment-13130376 Compile any Zig file (can be empty) with `-mcpu=baseline+soft_float` for x86_64 to be met with the following: ```sh-session $ zig build-exe minimal.zig -target x86_64-linux -mcpu=baseline+soft_float LLVM ERROR: Do not know how to soften the result of this operator! Aborted (core dumped) $ ] compiler_rt └─ [2528/2528] Linking └─ LLVM Emit Object [797] Semantic Analysis └─ process.SpawnOptions ``` I tried versions dating back to 0.11.0 and consistently got a crash on all of them. It looks like 0.14.1 has the most useful error message out of the releases: ```sh-session $ zig version 0.14.1 $ zig build-exe minimal.zig -target x86_64-linux -mcpu=baseline+soft_float LLVM ERROR: Cannot select: 0x7fc9edf16950: i32 = X86ISD::CMP undef:i1, Constant:i1<0>, mulc3.zig:61:31 @[ mulxc3.zig:13:23 ] 0x7fc9ee69b7f0: i1 = undef 0x7fc9edd40240: i1 = Constant<0> In function: __mulxc3 Aborted (core dumped) zig build-exe minimal.zig -target x86_64-linux -mcpu=baseline+soft_float ``` ### Expected Behavior The compiler shouldn't crash.

sagehane added the

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2026年04月15日 13:48:29 +02:00

alexrp added the

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2026年04月15日 13:53:41 +02:00

alexrp commented

2026年04月15日 13:54:51 +02:00

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Next step here is grabbing the LLVM IR, reducing it with llvm-reduce, and reporting an upstream bug.

Next step here is grabbing the LLVM IR, reducing it with `llvm-reduce`, and reporting an upstream bug.

alexrp commented

2026年05月06日 16:15:20 +02:00

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Duplicate: https://github.com/ziglang/zig/issues/12227

alexrp closed this issue

2026年05月06日 16:15:24 +02:00

sagehane commented

2026年05月07日 01:20:19 +02:00

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I see how #31856 is an un-noteworthy duplicate. This one hits an LLVM error, so is there some relevance from the perspective of upstream?

Edit: I guess it's a duplicate there too, of https://github.com/llvm/llvm-project/issues/56351.

I see how https://codeberg.org/ziglang/zig/issues/31856 is an un-noteworthy duplicate. This one hits an LLVM error, so is there some relevance from the perspective of upstream? Edit: I guess it's a duplicate there too, of https://github.com/llvm/llvm-project/issues/56351.

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zig build-exe crash on x86_64 with soft-float enabled #31878

Zig Version

Steps to Reproduce and Observed Behavior

Expected Behavior

`zig build-exe` crash on x86_64 with soft-float enabled #31878