Change PHINodes to store simple pointers to their incoming basic blocks,
instead of full-blown Uses.

Note that this loses an optimization in SplitCriticalEdge(), because we
can no longer walk the use list of a BasicBlock to find phi nodes. See
the comment I removed starting "However, the foreach loop is slow for
blocks with lots of predecessors".

Extend replaceAllUsesWith() on a BasicBlock to also update any phi
nodes in the block's successors. This mimics what would have happened
when PHINodes were proper Users of their incoming blocks. (Note that
this only works if OldBB->replaceAllUsesWith(NewBB) is called when
OldBB still has a terminator instruction, so it still has some
successors.)

llvm-svn: 133435

Change various bits of code to make better use of the existing PHINode
API, to insulate them from forthcoming changes in how PHINodes store
their operands.

llvm-svn: 133434

all over the place in different styles and variants.  Standardize on two
preferred entrypoints: one that takes a StructType and ArrayRef, and one that
takes StructType and varargs.

In cases where there isn't a struct type convenient, we now add a
ConstantStruct::getAnon method (whose name will make more sense after a few
more patches land).  

It would be "really really nice" if the ConstantStruct::get and 
ConstantVector::get methods didn't make temporary std::vectors.

llvm-svn: 133412

much cleaner.

llvm-svn: 133364

In cases such as the attached test, where the case value for a switch
destination is used in a phi node that follows the destination, it
might be better to replace that value with the condition value of the
switch, so that more blocks can be folded away with
TryToSimplifyUncondBranchFromEmptyBlock because there are less
conflicts in the phi node.

llvm-svn: 133344

type's bitwidth matches the (allocated) size of the alloca. This severely
pessimizes vector scalar replacement when the only vector type being used is
something like <3 x float> on x86 or ARM whose allocated size matches a
<4 x float>.

I hope to fix some of the flawed assumptions about allocated size throughout
scalar replacement and reenable this in most cases.

llvm-svn: 133338

alloca. Fixes part of <rdar://problem/9580800>.

llvm-svn: 133336

unless ScalarKind is Vector.

llvm-svn: 133335

llvm-svn: 133301

llvm-svn: 133298

Followup to 132926.  rdar://problem/9265821

llvm-svn: 133285

llvm-svn: 133251

than trying to insert them immediately after the invoke.

llvm-svn: 133188

llvm-svn: 133108

llvm-svn: 133086

llvm-svn: 133085

llvm-svn: 133078

Stop using memdep for a check that didn't really make sense with memdep. In terms of specific issues, using memdep here checks irrelevant instructions and won't work properly once we start returning "unknown" more aggressively from memdep.

llvm-svn: 133035

Add "unknown" results for memdep, which mean "I don't know whether a dependence for the given instruction exists in the given block".  This cleans up all the existing hacks in memdep which represent this concept by returning clobber with various unrelated instructions.

llvm-svn: 133031

llvm-svn: 132982

line info correctly.

llvm-svn: 132961

llvm-svn: 132954

llvm-svn: 132952

llvm-svn: 132940

llvm-svn: 132939

llvm-svn: 132938

spartan right now, but I plan to encode more information in this enum to improve
the correctness and reliability of SRoA. At least this first pass makes it
possible to make VectorTy an actual VectorType.

llvm-svn: 132937

llvm-svn: 132936

might overflow.  Re-typing the alloca to a larger type (e.g. double)
hoists a shift into the alloca, potentially exposing overflow in the
expression.  rdar://problem/9265821

llvm-svn: 132926

The backend already knew this trick.

llvm-svn: 132915

intrinsics. In fact, we'll optimize a bitcast to that when possible. Detect it
when looking for the lifetime intrinsics.

No test case, noticed by inspection.

llvm-svn: 132906

InstCombine: Shrink ((zext X) & C1) == C2 to fold away the cast if the "zext" and the "and" have one use.

llvm-svn: 132897

llvm-svn: 132896

llvm-svn: 132803

pad, separating the exception and selector calls from the new lpad.  Teaching
it not to do that, or to properly adjust the CFG afterwards, is out of
scope because it would require the other edges to the landing pad to be split
as well (effectively).  Instead, just recover from the most likely cases
during inlining.  The best long-term solution is to change the exception
representation and commit to either requiring or not requiring the more
complex edge-splitting logic;  this is just a shorter-term hack.

llvm-svn: 132799

llvm-svn: 132797

llvm-svn: 132775

llvm-svn: 132767

assuming that all offsets are legal vector accesses, and thus trying to access
the float member of { <2 x float>, float } as the 3rd element of the first
member.

llvm-svn: 132766

former was using the size of the entire alloca, whereas the latter was correctly using
the allocated size of the immediate type being converted (which may differ from the size
of the alloca). This fixes PR10082.

llvm-svn: 132759