Remove restriction on isize/usize in repr(simd)

[lambda]

As discussed in #55078, there's no known reason for this restriction.

It's unlikely that repr(simd) will be stabilized in its current form, but
might as well remove some restrictions on it.

This removes the branch in is_machine which returns false for these types.
is_machine is only used for the repr(simd) type validation check.

[rust-highfive]

r? @alexcrichton

(rust_highfive has picked a reviewer for you, use r? to override)

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:19b38dc0:start=1552629816587646881,finish=1552629817544235677,duration=956588796
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
Setting environment variables from .travis.yml
---
[01:14:15] .................................................................................................... 4400/5467
[01:14:18] .................................................................................................... 4500/5467
[01:14:22] .................................................................................................... 4600/5467
[01:14:27] ...........i........................................................................................ 4700/5467
[01:14:32] .................................................................F.................................. 4800/5467
[01:14:40] .................................................................................................... 5000/5467
[01:14:43] .................................................................................................... 5100/5467
[01:14:47] .................................................................................................... 5200/5467
[01:14:50] .................................................................................................... 5300/5467
[01:14:50] .................................................................................................... 5300/5467
[01:14:53] .................................................................................................... 5400/5467
[01:14:55] .....i.............................................................
[01:14:55] failures:
[01:14:55] 
[01:14:55] ---- [ui] ui/simd-type.rs stdout ----
[01:14:55] diff of stderr:
[01:14:55] 
[01:14:55] 10 LL | struct i64f64(i64, f64);
[01:14:55] 11    | ^^^^^^^^^^^^^^^^^^^^^^^^ SIMD elements must have the same type
[01:14:55] 12 
[01:14:55] - error[E0077]: SIMD vector element type should be machine type
[01:14:55] -    |
[01:14:55] -    |
[01:14:55] - LL | struct int4(isize, isize, isize, isize);
[01:14:55] + error: aborting due to 2 previous errors
[01:14:55] 18 
[01:14:55] - error: aborting due to 3 previous errors
[01:14:55] - 
[01:14:55] - 
[01:14:55] - Some errors occurred: E0075, E0076, E0077.
[01:14:55] + Some errors occurred: E0075, E0076.
[01:14:55] 22 For more information about an error, try `rustc --explain E0075`.
[01:14:55] 23 
[01:14:55] 
[01:14:55] 
[01:14:55] The actual stderr differed from the expected stderr.
[01:14:55] Actual stderr saved to /checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/simd-type/simd-type.stderr
[01:14:55] To update references, rerun the tests and pass the `--bless` flag
[01:14:55] To only update this specific test, also pass `--test-args simd-type.rs`
[01:14:55] error: 1 errors occurred comparing output.
[01:14:55] status: exit code: 1
[01:14:55] status: exit code: 1
[01:14:55] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/simd-type.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/simd-type/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/simd-type/auxiliary" "-A" "unused"
[01:14:55] ------------------------------------------
[01:14:55] 
[01:14:55] ------------------------------------------
[01:14:55] stderr:
[01:14:55] stderr:
[01:14:55] ------------------------------------------
[01:14:55] {"message":"SIMD vector cannot be empty","code":{"code":"E0075","explanation":"\nThe `#[simd]` attribute can only be applied to non empty tuple structs, because\nit doesn't make sense to try to use SIMD operations when there are no values to\noperate on.\n\nThis will cause an error:\n\n```compile_fail,E0075\n#![feature(repr_simd)]\n\n#[repr(simd)]\nstruct Bad;\n```\n\nThis will not:\n\n```\n#![feature(repr_simd)]\n\n#[repr(simd)]\nstruct Good(u32);\n```\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/simd-type.rs","byte_start":70,"byte_end":83,"line_start":5,"line_end":5,"column_start":1,"column_end":14,"is_primary":true,"text":[{"text":"struct empty; //~ ERROR SIMD vector cannot be empty","highlight_start":1,"highlight_end":14}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[],"rendered":"error[E0075]: SIMD vector cannot be empty\n  --> /checkout/src/test/ui/simd-type.rs:5:1\n   |\nLL | struct empty; //~ ERROR SIMD vector cannot be empty\n   | ^^^^^^^^^^^^^\n\n"}
[01:14:55] {"message":"SIMD vector should be homogeneous","code":{"code":"E0076","explanation":"\nWhen using the `#[simd]` attribute to automatically use SIMD operations in tuple\nstruct, the types in the struct must all be of the same type, or the compiler\nwill trigger this error.\n\nThis will cause an error:\n\n```compile_fail,E0076\n#![feature(repr_simd)]\n\n#[repr(simd)]\nstruct Bad(u16, u32, u32);\n```\n\nThis will not:\n\n```\n#![feature(repr_simd)]\n\n#[repr(simd)]\nstruct Good(u32, u32, u32);\n```\n"},"level":"error","spans":[{"file_name":"/checkout/src/test/ui/simd-type.rs","byte_start":137,"byte_end":161,"line_start":8,"line_end":8,"column_start":1,"column_end":25,"is_primary":true,"text":[{"text":"struct i64f64(i64, f64); //~ ERROR SIMD vector should be homogeneous","highlight_start":1,"highlight_end":25}],"label":"SIMD elements must have the same type","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[],"rendered":"error[E0076]: SIMD vector should be homogeneous\n  --> /checkout/src/test/ui/simd-type.rs:8:1\n   |\nLL | struct i64f64(i64, f64); //~ ERROR SIMD vector should be homogeneous\n   | ^^^^^^^^^^^^^^^^^^^^^^^^ SIMD elements must have the same type\n\n"}
[01:14:55] {"message":"aborting due to 2 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 2 previous errors\n\n"}
[01:14:55] {"message":"Some errors occurred: E0075, E0076.","code":null,"level":"","spans":[],"children":[],"rendered":"Some errors occurred: E0075, E0076.\n"}
[01:14:55] 
[01:14:55] ------------------------------------------
[01:14:55] 
[01:14:55] thread '[ui] ui/simd-type.rs' panicked at 'explicit panic', src/tools/compiletest/src/runtest.rs:3325:9
---
[01:14:55] 
[01:14:55] thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:496:22
[01:14:55] 
[01:14:55] 
[01:14:55] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-6.0/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "6.0.0\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
[01:14:55] 
[01:14:55] 
[01:14:55] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:14:55] Build completed unsuccessfully in 0:04:28
[01:14:55] Build completed unsuccessfully in 0:04:28
[01:14:55] make: *** [check] Error 1
[01:14:55] Makefile:48: recipe for target 'check' failed
The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0ded0401
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
Fri Mar 15 07:18:44 UTC 2019

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[alexcrichton]

@bors: r+

[bors]

📌 Commit 5303c1b has been approved by alexcrichton