It's becoming clear that LoopSimplify needs to unconditionally create loop preheaders. But that is a bigger fix. For now, continuing to hack LSR.
Fixes rdar://10701050 "Cannot split an edge from an IndirectBrInst" assert.

llvm-svn: 148288

llvm-svn: 148284

llvm-svn: 148252

llvm-svn: 148216

Fixup for r148132. Type replacement for LoopsProperties: from DenseMap to std::map, since we need to keep a valid pointer to properties of current loop.

Message for r148132:
LoopUnswitch: All helper data that is collected during loop-unswitch iterations was moved to separated class (LUAnalysisCache).

llvm-svn: 148215

llvm-svn: 148164

llvm-svn: 148149

llvm-svn: 148133

LoopUnswitch: All helper data that is collected during loop-unswitch iterations was moved to separated class (LUAnalysisCache). 

llvm-svn: 148132

the optimizer doesn't eliminate objc_retainBlock calls which are needed
for their side effect of copying blocks onto the heap.
This implements rdar://10361249.

llvm-svn: 148076

Re-fix the issue Bill fixed in r147899 in a slightly different way, which doesn't abuse the semantics of linker_private.  We don't really want to merge any string constant with a weak_odr global.

llvm-svn: 147971

[asan] extend the workaround for http://llvm.org/bugs/show_bug.cgi?id=11395: don't instrument the function at all on x86_32 if it has a large asm blob

llvm-svn: 147953

1. Size heuristics changed. Now we calculate number of unswitching
branches only once per loop.
2. Some checks was moved from UnswitchIfProfitable to
processCurrentLoop, since it is not changed during processCurrentLoop
iteration. It allows decide to skip some loops at an early stage.
Extended statistics:
- Added total number of instructions analyzed.

llvm-svn: 147935

with other symbols.

An object in the __cfstring section is suppoed to be filled with CFString
objects, which have a pointer to ___CFConstantStringClassReference followed by a
pointer to a __cstring. If we allow the object in the __cstring section to be
merged with another global, then it could end up in any section. Because the
linker is going to remove these symbols in the final executable, we shouldn't
bother to merge them.
<rdar://problem/10564621>

llvm-svn: 147899

These heuristics are sufficient for enabling IV chains by
default. Performance analysis has been done for i386, x86_64, and
thumbv7. The optimization is rarely important, but can significantly
speed up certain cases by eliminating spill code within the
loop. Unrolled loops are prime candidates for IV chains. In many
cases, the final code could still be improved with more target
specific optimization following LSR. The goal of this feature is for
LSR to make the best choice of induction variables.

Instruction selection may not completely take advantage of this
feature yet. As a result, there could be cases of slight code size
increase.

Code size can be worse on x86 because it doesn't support postincrement
addressing. In fact, when chains are formed, you may see redundant
address plus stride addition in the addressing mode. GenerateIVChains
tries to compensate for the common cases.

On ARM, code size increase can be mitigated by using postincrement
addressing, but downstream codegen currently misses some opportunities.

llvm-svn: 147826

After collecting chains, check if any should be materialized. If so,
hide the chained IV users from the LSR solver. LSR will only solve for
the head of the chain. GenerateIVChains will then materialize the
chained IV users by computing the IV relative to its previous value in
the chain.

In theory, chained IV users could be exposed to LSR's solver. This
would be considerably complicated to implement and I'm not aware of a
case where we need it. In practice it's more important to
intelligently prune the search space of nontrivial loops before
running the solver, otherwise the solver is often forced to prune the
most optimal solutions. Hiding the chained users does this well, so
that LSR is more likely to find the best IV for the chain as a whole.

llvm-svn: 147801

This collects a set of IV uses within the loop whose values can be
computed relative to each other in a sequence. Following checkins will
make use of this information.

llvm-svn: 147797

llvm-svn: 147785

llvm-svn: 147779

This subsumes several other transforms while enabling us to catch more cases.

llvm-svn: 147777

We still save an instruction when just the "and" part is replaced.
Also change the code to match comments more closely.

llvm-svn: 147753

InstCombine: If we have a bit test and a sign test anded/ored together, merge the sign bit into the bit test.

This is common in bit field code, e.g. checking if the first or the last bit of a bit field is set.

llvm-svn: 147749

This will be more important as we extend the LSR pass in ways that don't rely on the formula solver. In particular, we need it for constructing IV chains.

llvm-svn: 147724

LoopSimplify may not run on some outer loops, e.g. because of indirect
branches. SCEVExpander simply cannot handle outer loops with no preheaders.
Fixes rdar://10655343 SCEVExpander segfault.

llvm-svn: 147718

llvm-svn: 147711

llvm-svn: 147707

llvm-svn: 147667

present in the bottom of the CFG triangle, as the transformation isn't
ever valuable if the branch can't be eliminated.

Also, unify some heuristics between SimplifyCFG's multiple
if-converters, for consistency.

This fixes rdar://10627242.

llvm-svn: 147630

PR11705, part 2: globalopt shouldn't put inttoptr/ptrtoint operations into global initializers if there's an implied extension or truncation.

llvm-svn: 147625

code can incorrectly move the load across a store. This never
happens in practice today, but only because the current
heuristics accidentally preclude it.

llvm-svn: 147623

Eliminate the dead test for it on each loop iteration. No functionality change.

llvm-svn: 147616

llvm-svn: 147529

nsw bits on them.

llvm-svn: 147528

'and' that would zero out the trailing bits, and to produce an exact shift
ourselves.

llvm-svn: 147391

captured. This allows the tracker to look at the specific use, which may be
especially interesting for function calls.

Use this to fix 'nocapture' deduction in FunctionAttrs. The existing one does
not iterate until a fixpoint and does not guarantee that it produces the same
result regardless of iteration order. The new implementation builds up a graph
of how arguments are passed from function to function, and uses a bottom-up walk
on the argument-SCCs to assign nocapture. This gets us nocapture more often, and
does so rather efficiently and independent of iteration order.

llvm-svn: 147327

llvm-svn: 147307

llvm-svn: 147292

llvm-svn: 147291

to discard weights when appropriate. Still more to do (and a new TODO), but
it's a start!

llvm-svn: 147286

llvm-svn: 147284