Binding non-alias arguments with type parameters fails in llvm

[brson]

make stage2/std.o CFG_DISABLE_OPTIMIZE=1 results in the following:

Instruction does not dominate all uses!
  %20 = load %tydesc** %19
  store %tydesc* %20, %tydesc** %7
Broken module found, compilation aborted!
Stack dump:
0.      Running pass 'Function Pass Manager' on module 'rust_out'.
1.      Running pass 'Module Verifier' on function '@_rust_thunk1273_deque_create_grow'
Aborted

The following test cases reproduces:

fn grow[T](vec[T] elts) {
  auto copy_op = bind grow[T](elts);
}

fn main() {
}

And fails with the following:

Instruction does not dominate all uses!
  %19 = load %tydesc** %18
  store %tydesc* %19, %tydesc** %6
Broken module found, compilation aborted!
Stack dump:
0.      Running pass 'Function Pass Manager' on module 'rust_out'.
1.      Running pass 'Module Verifier' on function '@_rust_thunk17_grow'
Aborted

The code generated for the thunk in the test case looks like:

define internal fastcc void @_rust_thunk17_grow(i1*, %task*, %10*) {
allocas:
  %3 = alloca [1 x %tydesc*]
  %4 = alloca %tydesc
  %5 = alloca %13*
  br label %copy_args

copy_args:                                        ; preds = %allocas                                                                              
  br label %derived_tydescs

derived_tydescs:                                  ; preds = %copy_args                                                                            
  %6 = getelementptr [1 x %tydesc*]* %3, i32 0, i32 0
  store %tydesc* %19, %tydesc** %6
  %7 = load %tydesc* @_rust_tydesc11_grow
  store %tydesc %7, %tydesc* %4
  %8 = getelementptr %tydesc* %4, i32 0, i32 0
  %9 = getelementptr [1 x %tydesc*]* %3, i32 0, i32 0
  %10 = getelementptr %tydesc* %4, i32 0, i32 0
  store %tydesc** %9, %tydesc*** %10
  %11 = getelementptr %tydesc* %4, i32 0, i32 1
  store i32 ptrtoint (i1** getelementptr (i1** null, i32 1) to i32), i32* %11
  %12 = getelementptr %tydesc* %4, i32 0, i32 2
  store i32 ptrtoint (i1** getelementptr (%15* null, i64 0, i32 1) to i32), i32* %12
  br label %13

; <label>:13                                      ; preds = %derived_tydescs                                                                      
  %14 = bitcast %10* %2 to %20*
  %15 = getelementptr %20* %14, i32 0, i32 1, i32 1
  %16 = getelementptr %22* %15, i32 0, i32 1
  %17 = load %10** %16
  %18 = getelementptr %20* %14, i32 0, i32 1, i32 3, i32 0
  %19 = load %tydesc** %18
  %20 = getelementptr %20* %14, i32 0, i32 1, i32 2, i32 0
  %21 = load %13** %20
  store %13* %21, %13** %5
  %22 = bitcast %13** %5 to i8*
  %23 = getelementptr %tydesc* %4, i32 0, i32 0
  %24 = load %tydesc*** %23
  %25 = getelementptr %tydesc* %4, i32 0, i32 3
  %26 = load void (i1*, %task*, i1*, %tydesc**, i8*)** %25
  call fastcc void %26(i1* null, %task* %1, i1* null, %tydesc** %24, i8* %22)
  %27 = getelementptr %22* %15, i32 0, i32 0
  %28 = bitcast void (i1*, %task*, %10*, %13*)** %27 to void (i1*, %task*, %10*, %tydesc*, %13*)**
  %29 = load void (i1*, %task*, %10*, %tydesc*, %13*)** %28
  call fastcc void %29(i1* %0, %task* %1, %10* %17, %tydesc* %19, %13* %21)
  ret void
}

Note that this only happens when generating unoptimized code - the verifier runs after the optimizer, which seems to hide problems in code generation.

[brson]

It appears to only happen for non-alias bound arguments with type parameters.

[brson]

I committed a workaround for the issue in the standard library, but it can still be reproduced with the provided test case

[brson]

Optimization no longer needs to be disabled to reproduce this

[msullivan]

A very reduced test case:

fn oops[A](@A x)  {
    bind oops(x);
}

[msullivan]

Closed by #645.