llvm-svn: 60268

If we see that a load depends on the allocation of its memory with no
intervening stores, we now return a 'None' depedency instead of "Normal".
This tweaks GVN to do its optimization with the new result.

llvm-svn: 60267

method that returns its result as a DepResultTy instead of as a
MemDepResult.  This reduces conversion back and forth.

llvm-svn: 60266

the file, no functionality change.

llvm-svn: 60265

comments about what this class does.

llvm-svn: 60264

dependencies.  The basic situation was this: consider if we had:

  store1
  ...
  store2
  ...
  store3

Where memdep thinks that store3 depends on store2 and store2 depends 
on store1.  The problem happens when we delete store2: The code in 
question was updating dep info for store3 to be store1.  This is a
spiffy optimization, but is not safe at all, because aliasing isn't
transitive.  This bug isn't exposed today with DSE because DSE will only
zap store2 if it is identifical to store 3, and in this case, it is 
safe to update it to depend on store1.  However, memcpyopt is not so
fortunate, which is presumably why the "dropInstruction" code used to
exist.

Since this doesn't actually provide a speedup in practice, just rip the
code out.

llvm-svn: 60263

Fix a subtle iterator invalidation bug I introduced in the last commit.

llvm-svn: 60258

an entry in the nonlocal deps map, don't reset entries
referencing that instruction to [dirty, null], instead, set
them to [dirty,next] where next is the instruction after the
deleted one.  Use this information in the non-local deps
code to avoid rescanning entire blocks.

This speeds up GVN slightly by avoiding pointless work.  On
403.gcc this makes GVN 1.5% faster. 

llvm-svn: 60256

a smallvector instead of a DenseMap.  This speeds up GVN by 5%
on 403.gcc.

llvm-svn: 60255

no functionality/code change.

llvm-svn: 60254

formulation that is faster and doesn't require nonLazyHelper.
Much less code.

llvm-svn: 60253

llvm-svn: 60242

llvm-svn: 60241

Put a some code back to handle buggy behavior that GVN expects: it wants
loads to depend on each other, and accesses to depend on their allocations.

llvm-svn: 60240

Use getTypeStoreSize instead of ABITypeSize for in-memory size
in a couple places.

llvm-svn: 60238

former does caching, the later doesn't.  This dramatically simplifies
the logic in getDependency and getDependencyFrom.

llvm-svn: 60234

Document the Dirty value more precisely, use it for the uninitialized
DepResultTy value.  Change reverse mappings to be from an instruction*
instead of DepResultTy, and stop tracking other forms.  This makes it more
clear that we only care about the instruction cases.

Eliminate a DepResultTy,bool pair by using Dirty in the local case as well,
shrinking the map and simplifying the code.

This speeds up GVN by ~3% on 403.gcc.

llvm-svn: 60232

query.  This makes it crystal clear what cases can escape from MemDep that
the clients have to handle.  This also gives the clients a nice simplified
interface to it that is easy to poke at.

This patch also makes DepResultTy and MemoryDependenceAnalysis::DepType
private, yay.

llvm-svn: 60231

of a pointer/int pair instead of a manually bitmangled pointer.
This forces clients to think a little more about checking the 
appropriate pieces and will be useful for internal 
implementation improvements later.

I'm not particularly happy with this.  After going through this
I don't think that the clients of memdep should be exposed to
the internal type at all.  I'll fix this in a subsequent commit.

This has no functionality change.

llvm-svn: 60230

properly updates the reverse dependency map when it installs updated 
dependencies for instructions that depend on the removed instruction.

llvm-svn: 60222

no functionality change.

llvm-svn: 60219

llvm-svn: 60218

This shows the root problem behind PR3141.

llvm-svn: 60216

but it doesn't make any sense at all.

Also make the method const, private, and fit in 80 cols while we're at it.

llvm-svn: 60215

llvm-svn: 60211

llvm-svn: 56116

circumstances we could end up remapping a dependee to the same instruction 
that we're trying to remove.  Handle this properly by just falling back to
a conservative solution.

llvm-svn: 54132

llvm-svn: 53032

This fixes PR2503, though we should also fix other passes not to emit this kind of code.

llvm-svn: 52946

llvm-svn: 51846

llvm-svn: 51845

instruction.  This fixes some Ada miscompiles reported in PR2324.

llvm-svn: 51069

several things that were neither in an anonymous namespace nor static
but not intended to be global.

llvm-svn: 51017

llvm-svn: 50696

llvm-svn: 49842

llvm-svn: 49504

wrong order.

llvm-svn: 49499

not the end.

llvm-svn: 48999

llvm-svn: 48579

llvm-svn: 48554