Get rid of an optimization in SCCP which appears to have many issues.  Specifically, it doesn't handle many cases involving undef correctly, and it is missing other checks which
lead to it trying to re-mark a value marked as a constant with a different value.  It also appears to trigger very rarely.

Fixes PR11357.

llvm-svn: 144352

Make sure IPSCCP never marks a tracked call as overdefined in SCCPSolver::ResolvedUndefsIn.  If we do, we can end up in a situation where a function is resolved to return a constant, but the caller is marked overdefined, which confuses the code later.

<rdar://problem/9956541> (again).

llvm-svn: 140210

Use Duncan's patch to delete the instructions in reverse order (minus the landingpad and terminator).

llvm-svn: 139090

llvm-svn: 139023

Duncan noticed this!

llvm-svn: 138967

The landingpad instruction is required in the landing pad block. Because we're
not deleting terminating instructions, the invoke may still jump to here (see
Transforms/SCCP/2004-11-16-DeadInvoke.ll). Remove all uses of the landingpad
instruction, but keep it around until code-gen can remove the basic block.

llvm-svn: 138890

Silly mistake from r137777; restore significant isStructTy() checks.  While here, be a bit more defensive
with unknown instructions.

Fixes PR10687.

llvm-svn: 137836

making random bad assumptions about instructions which are not explicitly listed.  

Includes fix for rdar://9956541, a version of "undef ^ undef should return
0 because it's easier than arguing with users".

llvm-svn: 137777

Minor bug in SCCP found by inspection.  (I don't think it's possible to hit this with a normal pass pipeline, but fixing for completeness.)

llvm-svn: 137755

This implements the 'landingpad' instruction. It's used to indicate that a basic
block is a landing pad. There are several restrictions on its use (see
LangRef.html for more detail). These restrictions allow the exception handling
code to gather the information it needs in a much more sane way.

This patch has the definition, implementation, C interface, parsing, and bitcode
support in it.

llvm-svn: 137501

llvm-svn: 136723

This adds the 'resume' instruction class, IR parsing, and bitcode reading and
writing. The 'resume' instruction resumes propagation of an existing (in-flight)
exception whose unwinding was interrupted with a 'landingpad' instruction (to be
added later).

llvm-svn: 136589

r136339, r136341, r136369, r136387, r136392, r136396, r136429, r136430, r136444,
r136445, r136446, r136253 pending review.

llvm-svn: 136556

This adds the new instructions 'landingpad' and 'resume'.

llvm-svn: 136253

llvm-svn: 136205

llvm-svn: 135973

ConstantExpr::getInBoundsGetElementPtr to use ArrayRef.

llvm-svn: 135673

to for it to be an an anon namespace and be in a header.

Eliminate some extraenous uses of tie.

llvm-svn: 135669

llvm-svn: 135477

llvm-svn: 135375

consistently.

llvm-svn: 131803

Luis Felipe Strano Moraes!

llvm-svn: 129558

instructions.

llvm-svn: 123973

llvm-svn: 123573

there should be a better way to do this.  PR 8679.

llvm-svn: 120457

Get rid of static constructors for pass registration.  Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.

llvm-svn: 116820

llvm-svn: 115996

llvm-svn: 111344

before it rewrites the code, we need to use that in the post-rewrite pass.

llvm-svn: 110962

llvm-svn: 110460

llvm-svn: 110410

ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396

llvm-svn: 109687

llvm-svn: 109045

llvm-svn: 102358

forced constant is changed to a constant, we would end
up adding the instruction to the wrong worklist, 
preventing it from being properly revisited.  This fixes
rdar://7832370

llvm-svn: 100837

undefs in branches/switches, we have two cases: a branch on a literal
undef or a branch on a symbolic value which is undef.  If we have a
literal undef, the code was correct: forcing it to a constant is the
right thing to do.

If we have a branch on a symbolic value that is undef, we should force
the symbolic value to a constant, which then makes the successor block
live.  Forcing the condition of the branch to being a constant isn't 
safe if later paths become live and the value becomes overdefined.  This
is the case that 'forcedconstant' is designed to handle, so just use it.

This fixes rdar://7765019 but there is no good testcase for this, the
one I have is too insane to be useful in the future.

llvm-svn: 100478

is necessary. Inherits from new templated baseclass CallSiteBase<>
which is highly customizable. Base CallSite on it too, in a configuration
that allows full mutation.
Adapt some call sites in analyses to employ ImmutableCallSite.

llvm-svn: 100100

llvm-svn: 99564

I have audited all getOperandNo calls now, fixing
hidden assumptions. CallSite related uglyness will
be eliminated successively.

Note this patch has a long and griveous history,
for all the back-and-forths have a look at
CallSite.h's log.

llvm-svn: 99399