Extend MIR inlining to all operand variants

[pvdrz]

This fixes #54193
r? @eddyb

[wesleywiser]

Code changes look good to me. Can you also write a test that shows that let f = foo; f() inlines correctly? (See src/test/mir-opt/inline-closure-borrows-arg.rs for an example)

[pvdrz]

Of course! give me a couple minutes to do it :)

[pvdrz]

Something like this

fn foo() -> i32 {
    let f = |x: i32, y: i32| x + y;
    f(1, -1)
}

would be a good test? Or did I misunderstood something?

[wesleywiser]

I think we want something like:

fn foo(x: i32, y: i32) -> i32 {
  x + y
}

fn main() {
  let f = foo;
  println!("{}", f(1, 2));
}

[pvdrz]

But then how do I check that the MIR code is in fact what we want? Should I do something like

fn foo(x: i32, y: i32) -> i32 {
  x + y
}

fn bar() -> i32 {
  let f = foo;
  f(1, 2)
}

fn main() {
  println!("{}", bar());
}

And then check that inside bar everything is inlined?

[wesleywiser]

Yeah, that looks right to me. Sorry, I don't have a compiler available at the moment so I can't give you the specific MIR instruction but we want to make sure that foo is inlined inside bar which can be done by verifying that the + operation happens inside bar.

[pvdrz]

Bad news, I'm getting

fn bar() -> i32{
    let mut _0: i32;
    scope 1 {
    }
    scope 2 {
        let _1: fn(i32, i32) -> i32 {foo};
    }
    let mut _2: fn(i32, i32) -> i32 {foo};
    bb0: {                              
        StorageLive(_1);
        _1 = const foo;
        StorageLive(_2);
        _2 = _1;
        _0 = move _2(const 1i32, const -1i32) -> bb1;
    }
    bb1: {                              
        StorageDead(_2);
        StorageDead(_1);
        return;
    }
    bb2: {
        resume;
    }
}

Which means inlining is not happening.

[wesleywiser]

Does adding an #[inline(always)] to foo() make a difference?

[pvdrz]

Yeah it does! should I left the #[inline(always)]?

[wesleywiser]

Yeah, go ahead and leave it in. The goal is to verify let f = foo; f() can be inlined regardless of whether or not the optimizer actually decides it's a good idea.

[pvdrz]

Ok, I'll finish the test and commit again. Any name ideas for this test?

[wesleywiser]

I'd either go with inline-any-operand.rs or just plain old issue-54193.rs 🙂

[wesleywiser]

Thanks!!

@bors r+

[bors]

📌 Commit 99af55b44d9081acf27d998c3413a86188bc600b has been approved by wesleywiser

[bors]

⌛ Testing commit 99af55b44d9081acf27d998c3413a86188bc600b with merge 6100d69d31d30131798b14e0b99d9ecb885bd5fc...

[bors]

💔 Test failed - status-travis

[rust-highfive]

The job x86_64-gnu-nopt 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.

[01:21:36] test [mir-opt] mir-opt/lower_128bit_debug_test.rs ... ok
[01:21:36] 
[01:21:36] failures:
[01:21:36] 
[01:21:36] ---- [mir-opt] mir-opt/inline-any-operand.rs stdout ----
[01:21:36] thread '[mir-opt] mir-opt/inline-any-operand.rs' panicked at 'Did not find expected line, error: ran out of mir dump to match against
[01:21:36] Expected Line: "    _0 = Add(move _3, move _4);"
[01:21:36] Test Name: rustc.bar.Inline.after.mir
[01:21:36] ... (elided)
[01:21:36] ... (elided)
[01:21:36] bb0: {
[01:21:36] ... (elided)
[01:21:36] ... (elided)
[01:21:36]     _0 = Add(move _3, move _4);
[01:21:36] ... (elided)
[01:21:36]     return;
[01:21:36] }
[01:21:36] ... (elided)
[01:21:36] Actual:
[01:21:36] fn bar() -> i32{
[01:21:36]     let mut _0: i32;
[01:21:36]     scope 1 {
[01:21:36]         scope 3 {
[01:21:36]     }
[01:21:36]     scope 2 {
[01:21:36]     scope 2 {
[01:21:36]         let _1: fn(i32, i32) -> i32 {foo};
[01:21:36]     }
[01:21:36]     let mut _2: fn(i32, i32) -> i32 {foo};
[01:21:36]     let mut _3: (i32, bool);
[01:21:36]     let mut _4: i32;
[01:21:36]     let mut _5: i32;
[01:21:36]     bb0: {                              
[01:21:36]         StorageLive(_1);
[01:21:36]         _1 = const foo;
[01:21:36]         FakeRead(ForLet, _1);
[01:21:36]         StorageLive(_2);
[01:21:36]         _2 = _1;
[01:21:36]         _4 = const 1i32;
[01:21:36]         _5 = const -1i32;
[01:21:36]         _3 = CheckedAdd(move _4, move _5);
[01:21:36]         assert(!move (_3.1: bool), "attempt to add with overflow") -> bb1;
[01:21:36]     }
[01:21:36]     bb1: {                              
[01:21:36]         _0 = move (_3.0: i32);
[01:21:36]         StorageDead(_2);
[01:21:36]         StorageDead(_1);
[01:21:36]         return;
[01:21:36] }', tools/compiletest/src/runtest.rs:2893:13
[01:21:36] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:21:36] 
[01:21:36] 
---
[01:21:36] 
[01:21:36] thread 'main' panicked at 'Some tests failed', tools/compiletest/src/main.rs:496:22
[01:21:36] 
[01:21:36] 
[01:21:36] 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/mir-opt" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/mir-opt" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "mir-opt" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/checkout/obj/build/x86_64-unknown-linux-gnu/llvm/build/bin/FileCheck" "--host-rustcflags" "-Crpath -Zunstable-options " "--target-rustcflags" "-Crpath -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" "--llvm-version" "8.0.0svn\n" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
[01:21:36] 
[01:21:36] 
[01:21:36] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
[01:21:36] Build completed unsuccessfully in 0:17:33
[01:21:36] Build completed unsuccessfully in 0:17:33
[01:21:36] make: *** [check] Error 1
[01:21:36] Makefile:58: recipe for target 'check' failed

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0ace4c80
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
---
travis_time:end:3a03c314:start=1537730004150473770,finish=1537730004156518305,duration=6044535
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:06379c15
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:37001098
travis_time:start:37001098
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:0aa4c324
$ dmesg | grep -i kill

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)

[wesleywiser]

@bors r+

[bors]

📌 Commit 1e3c86e has been approved by wesleywiser

[bors]

⌛ Testing commit 1e3c86e with merge 4f1677a...

[bors]

💔 Test failed - status-appveyor

[pvdrz]

It seems it was a connection problem inside appveyor: https://ci.appveyor.com/project/rust-lang/rust/build/1.0.9089/job/w3c09bbqp6akf7ie#L7208

[wesleywiser]

Spurious network issue cc #40474

@bors retry

[bors]

⌛ Testing commit 1e3c86e with merge 5c875d9...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: wesleywiser
Pushing 5c875d9 to master...