Building for 32-bit ARM target fails in src/codegen/shuffle1_dyn.rs

[hsivonen]

This happens both when targeting Android and glibc:

(bionic)hsivonen@localhost:~/Projects/packed_simd$ RUSTFLAGS='-Z macro-backtrace' cargo build --target thumbv7neon-unknown-linux-gnueabihf --verbose
   Compiling cfg-if v0.1.10
     Running `rustc --crate-name cfg_if --edition=2018 /home/hsivonen/.cargo/registry/src/github.com-1285ae84e5963aae/cfg-if-0.1.10/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 -C metadata=eb2569c80076c7ec -C extra-filename=-eb2569c80076c7ec --out-dir /home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps --target thumbv7neon-unknown-linux-gnueabihf -L dependency=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps -L dependency=/home/hsivonen/Projects/packed_simd/target/debug/deps --cap-lints allow -Z macro-backtrace`
   Compiling libm v0.1.4
     Running `rustc --crate-name libm --edition=2018 /home/hsivonen/.cargo/registry/src/github.com-1285ae84e5963aae/libm-0.1.4/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="default"' --cfg 'feature="stable"' -C metadata=bbe286ea499eab57 -C extra-filename=-bbe286ea499eab57 --out-dir /home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps --target thumbv7neon-unknown-linux-gnueabihf -L dependency=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps -L dependency=/home/hsivonen/Projects/packed_simd/target/debug/deps --cap-lints allow -Z macro-backtrace`
   Compiling packed_simd_2 v0.3.4 (/home/hsivonen/Projects/packed_simd)
     Running `rustc --crate-name packed_simd_2 --edition=2018 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="default"' -C metadata=a0a4ef0e719e0d1f -C extra-filename=-a0a4ef0e719e0d1f --out-dir /home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps --target thumbv7neon-unknown-linux-gnueabihf -C incremental=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/incremental -L dependency=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps -L dependency=/home/hsivonen/Projects/packed_simd/target/debug/deps --extern cfg_if=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps/libcfg_if-eb2569c80076c7ec.rmeta --extern libm=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps/liblibm-bbe286ea499eab57.rmeta -Z macro-backtrace --cfg libcore_neon`
error[E0425]: cannot find value `y` in this scope
   --> src/codegen/shuffle1_dyn.rs:125:51
    |
28  | / macro_rules! impl_shuffle1_dyn {
29  | |     (u8x8) => {
30  | |         cfg_if! {
31  | |             if #[cfg(all(
...   |
125 | |                             let (i0, i1) = U { j: y }.s;
    | |                                                   ^ not found in this scope
...   |
271 | |     ($id:ident) => { impl_fallback!($id); }
272 | | }
    | |_- in this expansion of `impl_shuffle1_dyn!`
...
277 |   impl_shuffle1_dyn!(u8x16);
    |   -------------------------- in this macro invocation

error[E0425]: cannot find value `x` in this scope
   --> src/codegen/shuffle1_dyn.rs:128:48
    |
28  | / macro_rules! impl_shuffle1_dyn {
29  | |     (u8x8) => {
30  | |         cfg_if! {
31  | |             if #[cfg(all(
...   |
128 | |                                 mem::transmute(x),
    | |                                                ^ not found in this scope
...   |
271 | |     ($id:ident) => { impl_fallback!($id); }
272 | | }
    | |_- in this expansion of `impl_shuffle1_dyn!`
...
277 |   impl_shuffle1_dyn!(u8x16);
    |   -------------------------- in this macro invocation

error[E0425]: cannot find value `x` in this scope
   --> src/codegen/shuffle1_dyn.rs:132:48
    |
28  | / macro_rules! impl_shuffle1_dyn {
29  | |     (u8x8) => {
30  | |         cfg_if! {
31  | |             if #[cfg(all(
...   |
132 | |                                 mem::transmute(x),
    | |                                                ^ not found in this scope
...   |
271 | |     ($id:ident) => { impl_fallback!($id); }
272 | | }
    | |_- in this expansion of `impl_shuffle1_dyn!`
...
277 |   impl_shuffle1_dyn!(u8x16);
    |   -------------------------- in this macro invocation

error[E0308]: mismatched types
   --> src/codegen/shuffle1_dyn.rs:136:45
    |
28  | / macro_rules! impl_shuffle1_dyn {
29  | |     (u8x8) => {
30  | |         cfg_if! {
31  | |             if #[cfg(all(
...   |
136 | |                             let r = U { s: (r0, r1) }.j;
    | |                                             ^^ expected struct `Simd`, found struct `uint8x8_t`
...   |
271 | |     ($id:ident) => { impl_fallback!($id); }
272 | | }
    | |_- in this expansion of `impl_shuffle1_dyn!`
...
277 |   impl_shuffle1_dyn!(u8x16);
    |   -------------------------- in this macro invocation
    |
    = note: expected struct `Simd<[u8; 8]>`
               found struct `uint8x8_t`

error[E0308]: mismatched types
   --> src/codegen/shuffle1_dyn.rs:136:49
    |
28  | / macro_rules! impl_shuffle1_dyn {
29  | |     (u8x8) => {
30  | |         cfg_if! {
31  | |             if #[cfg(all(
...   |
136 | |                             let r = U { s: (r0, r1) }.j;
    | |                                                 ^^ expected struct `Simd`, found struct `uint8x8_t`
...   |
271 | |     ($id:ident) => { impl_fallback!($id); }
272 | | }
    | |_- in this expansion of `impl_shuffle1_dyn!`
...
277 |   impl_shuffle1_dyn!(u8x16);
    |   -------------------------- in this macro invocation
    |
    = note: expected struct `Simd<[u8; 8]>`
               found struct `uint8x8_t`

error: aborting due to 5 previous errors

Some errors have detailed explanations: E0308, E0425.
For more information about an error, try `rustc --explain E0308`.
error: could not compile `packed_simd_2`

Caused by:
  process didn't exit successfully: `rustc --crate-name packed_simd_2 --edition=2018 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --cfg 'feature="default"' -C metadata=a0a4ef0e719e0d1f -C extra-filename=-a0a4ef0e719e0d1f --out-dir /home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps --target thumbv7neon-unknown-linux-gnueabihf -C incremental=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/incremental -L dependency=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps -L dependency=/home/hsivonen/Projects/packed_simd/target/debug/deps --extern cfg_if=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps/libcfg_if-eb2569c80076c7ec.rmeta --extern libm=/home/hsivonen/Projects/packed_simd/target/thumbv7neon-unknown-linux-gnueabihf/debug/deps/liblibm-bbe286ea499eab57.rmeta -Z macro-backtrace --cfg libcore_neon` (exit code: 1)

rustc --version: rustc 1.49.0-nightly (31ee872db 2020-10-28)

[hsivonen]

It appears that the ARMv7 specialization of dynamic shuffles was been bogus, and fixing the typos in 026b10ed273c9e3db424f2f48f219d79b4bbc0d0 revealed it.

[workingjubilee]

Oh, that's "lovely". Thank you for finding that.