current translation unit as available_externally. 

This helps devirtualize the second example in PR3100, comment 18:

struct S { S() {}; virtual void xyzzy(); };
inline void foo(S *s) { s->xyzzy(); }
void bar() { S s; foo(&s); }

This involved four major changes:

1. In DefineUsedVTables, always mark virtual member functions as referenced for
   non-template classes and class template specializations.
2. In CodeGenVTables::ShouldEmitVTableInThisTU return true if optimizations are
   enabled, even if the key function is not implemented in this translation 
   unit. We don't ever do this for code compiled with -fapple-kext, because we
   don't ever want to devirtualize virtual member function calls in that case.
3. Give the correct linkage for vtables where the key function is not defined.
4. Update the linkage for RTTI structures when necessary.

llvm-svn: 124565

This is similar to the -unroll-threshold option. There should be no change in
behavior when -tail-dup-size is not explicit on the llc command line.

llvm-svn: 124564

and implemented it for the EmulateInstructionARM class.

llvm-svn: 124563

of the EmulateInstruction class.

llvm-svn: 124562

by PR9088 fixes things.

llvm-svn: 124561

to do this and more, but would only do it if X/Y had only one use.  Spotted as the
most common missed simplification in SPEC by my auto-simplifier, now that it knows
about nuw/nsw/exact flags.  This removes a bunch of multiplications from 447.dealII
and 483.xalancbmk.  It also removes a lot from tramp3d-v4, which results in much
more inlining.

llvm-svn: 124560

Teach DAGCombine to fold fold (sra (trunc (sr x, c1)), c2) -> (trunc (sra x, c1+c2) when c1 equals the amount of bits that are truncated off.

This happens all the time when a smul is promoted to a larger type.

On x86-64 we now compile "int test(int x) { return x/10; }" into
  movslq  %edi, %rax
  imulq $1717986919, %rax, %rax
  movq  %rax, %rcx
  shrq  $63, %rcx
  sarq  $34, %rax <- used to be "shrq $32, %rax; sarl $2, %eax"
  addl  %ecx, %eax

This fires 96 times in gcc.c on x86-64.

llvm-svn: 124559

invocation. 

This mimics what gcc does and fixes libtool check for libraries.

llvm-svn: 124558

llvm-svn: 124557

llvm-svn: 124556

llvm-svn: 124555

llvm-svn: 124554

When emitting RTTI for a non-class type, compute the visibility of the RTTI data based on the explicit visibility of the type.

llvm-svn: 124553

llvm-svn: 124552

llvm-svn: 124551

llvm-svn: 124550

I'm still not sure if having the typenames be visible with -hidden-weak-vtables, but I think it makes sense.

llvm-svn: 124549

Set the visibility for typeinfo names.

llvm-svn: 124548

This is the one where one of the branches of the select is another select on
the same condition.

llvm-svn: 124547

Change CodeGenModule::setTypeVisibility to take a TypeVisibilityKind enum instead of an "IsForRTTI" flag.

llvm-svn: 124546

The DEBUG() call at line 606 demands to see raw_ostream's definition. I have no idea why this seems to only break MSVC.

llvm-svn: 124545

llvm-svn: 124544

llvm-svn: 124543

llvm-svn: 124542

llvm-svn: 124541

llvm-svn: 124540

Make emitting a VTT a two-step process, much like emitting a VTable. You first get the address of the VTT, and then pass it to EmitVTTDefinition.

llvm-svn: 124539

llvm-svn: 124538

Add a new function, to be used by CGRTTI, CGVTables and CGVTT (which each has their own copy of this code).

llvm-svn: 124537

llvm-svn: 124536

llvm-svn: 124535

llvm-svn: 124534

llvm-svn: 124533

This happens e.g. for code like "X - X%10" where we lower the modulo operation
to a series of multiplies and shifts that are then subtracted from X, leading to
this missed optimization.

llvm-svn: 124532

llvm-svn: 124531

by name or by pid (with or without waiting for a process to launch) and
catch the response asynchronously.

llvm-svn: 124530

llvm-svn: 124529

When trying to get the most derived class, don't assume that we can ignore all casts. We can only ignore derived-to-base and no-op casts. Fixes selfhost.

llvm-svn: 124528

llvm-svn: 124527

llvm-svn: 124526