pointer bitcast when performing return slot optimization.

llvm-svn: 48343

Improve the return slot optimization to be both more aggressive (not limited to sret parameters), and 
safer (when the passed pointer might be invalid).  Thanks to Duncan and Chris for the idea behind this, 
and extra thanks to Duncan for helping me work out the trap-safety.

llvm-svn: 48280

in an invalid transformation.

llvm-svn: 47639

not safe.  This is fixed by more aggressively checking that the return slot is
not used elsewhere in the function.

llvm-svn: 47544

Fix an issue where GVN would try to use an instruction before its definition when performing return slot optimization.

llvm-svn: 47541

llvm-svn: 47371

llvm-svn: 47364

Refactor this method a bit, and correct a test that was completely wrong but happened to work out anyways. :-)

llvm-svn: 47321

llvm-svn: 47320

llvm-svn: 47319

llvm-svn: 47318

and add some others that should have been in from the first place.  Document the whole thing better.

llvm-svn: 47315

At some point in the future, this check will become smarter.

llvm-svn: 47310

over all the parameters of the callee looking for it.

llvm-svn: 47309

to apply to a memcpy into processInstruction.  Also, fix a bug in the check due to
missing braces.

llvm-svn: 47307

Fix Transforms/GVN/memcpy.ll, which Chris broke in r47275 by reordering the branches.  memcpy's are a kind of CallInst.

llvm-svn: 47305

llvm-svn: 47275

Add support to GVN for performing sret return slot optimization.  This means that, if an sret function tail calls
another sret function, it should pass its own sret parameter to the tail callee, allowing it to fill in the correct
return value.  llvm-gcc does not emit this by default.  Instead, it allocates space in the caller for the sret of
the tail call and then uses memcpy to copy the result into the caller's sret parameter.  This optimization detects
and optimizes that case.

llvm-svn: 47265

llvm-svn: 47111

bugs fixed.  This now passes PPC bootstrap.

llvm-svn: 47026

checks for a malloc/alloca immediately followed by a load.

llvm-svn: 47006

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20080128/057882.html

This is causing a miscompilation on PPC G5 and just now seeing it on iMac x86-64.

llvm-svn: 46822

llvm-svn: 46693

llvm-svn: 45418

Fix several cache coherence bugs in MemDep/GVN that were found.  Also add some (disabled) debugging code
to make such problems easier to diagnose in the future, written by Duncan Sands.

llvm-svn: 44695

into alias analysis.  This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter.  These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function.  Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite.  To reduce the
chance of misuse it is now protected.

llvm-svn: 44487

llvm-svn: 44437

llvm-svn: 44325

llvm-svn: 44323

llvm-svn: 43147

speedup for GVN.

llvm-svn: 42185

Add a new DenseMapInfo::isEqual method to allow clients to redefine
the equality predicate used when probing the hash table.

llvm-svn: 42042

llvm-svn: 41998

llvm-svn: 41131

llvm-svn: 41129

they're not related to eliminating a load.

llvm-svn: 41081

llvm-svn: 41080

llvm-svn: 41078

the function.

llvm-svn: 41077

llvm-svn: 40961