powerpc32: Expected no forward declarations! LLVM ERROR: Broken function found, compilation aborted!

[tonychain]

$ rustc --version
rustc 1.18.0-nightly (c58c928e6 2017-04-11)

$ cat /proc/cpuinfo
processor	: 0
cpu		: 7447A, altivec supported
clock		: 1499.999994MHz
revision	: 1.5 (pvr 8003 0105)

(that's a G4)

Here's an example of the error compiling rustc-serialize, but really it appears to be almost any crate. I've seen one crate (fake-simd) compile, but encounter this error on almost any others.

   Compiling rustc-serialize v0.3.23
     Running `rustc --crate-name rustc_serialize /home/tony/.cargo/registry/src/gh.neting.cc-eae4ba8cbf2ce1c7/rustc-serialize-0.3.23/src/lib.rs --crate-type lib --emit=dep-info,link -C debuginfo=2 -C metadata=77e9450ddf5d5cb1 -C extra-filename=-77e9450ddf5d5cb1 --out-dir /home/tony/src/test/rustseemodule/target/debug/deps -L dependency=/home/tony/src/test/rustseemodule/target/debug/deps --cap-lints allow`
Expected no forward declarations!
!2477 = <temporary!> !{}
LLVM ERROR: Broken function found, compilation aborted!
error: Could not compile `rustc-serialize`.

Caused by:
  process didn't exit successfully: `rustc --crate-name rustc_serialize /home/tony/.cargo/registry/src/gh.neting.cc-eae4ba8cbf2ce1c7/rustc-serialize-0.3.23/src/lib.rs --crate-type lib --emit=dep-info,link -C debuginfo=2 -C metadata=77e9450ddf5d5cb1 -C extra-filename=-77e9450ddf5d5cb1 --out-dir /home/tony/src/test/rustseemodule/target/debug/deps -L dependency=/home/tony/src/test/rustseemodule/target/debug/deps --cap-lints allow` (exit code: 1)

Sorry that's not a lot to go on, but I'm happy to provide any additional information you need to debug.

[pkgw]

I see this when running rustc on a fake PowerPC processor using qemu as well. The current nightly (rustc 1.25.0-nightly (7d6e5b9da 2018-01-27)) seems to succeed much more often than 1.24, but I still find crates where this error occurs repeatably.

[pkgw]

Compiling in release mode avoids the problem for me.

[glaubitz]

This seems to be the same as #50960.

[pkgw]

Still happens with Rust 1.27.0, FWIW.

[glaubitz]

Still happens with Rust 1.27.0, FWIW.

1.27.0 is too old. You will need at least 1.29.0, if I remember correctly. The bug was in LLVM and has been fixed, see #50960.

[pkgw]

Thanks, that's helpful to know. Can't close this bug myself, but happy to see it closed if this is fixed — looks like you've been pretty involved in #50960 so happy to defer to you on that.

[sanxiyn]

Closing, based on discussion at #50960.