The analysis will be needed by both the greedy register allocator and the
X86FloatingPoint pass. It only needs to be computed once when the CFG doesn't
change.

This pass is very fast, usually showing up as 0.0% wall time.

llvm-svn: 122832

warning is overzealous but gcc is what it is.)

llvm-svn: 122829

llvm-svn: 122828

llvm-svn: 122827

llvm-svn: 122826

Clarify terminology, settling on referring to what was the "number table" as the "leader table", and
rename methods to make it much more clear what they're doing.

llvm-svn: 122823

llvm-svn: 122822

case where a static caller is itself inlined everywhere else, and
thus may go away if it doesn't get too big due to inlining other
things into it.  If there are references to the caller other than
calls, it will not be removed; account for this.
This results in same-day completion of the case in PR8853.

llvm-svn: 122821

Branch instructions don't produce values, so there's no need to generate a value number for them.  This
avoids adding them to the various value numbering tables, resulting in a minor (~3%) speedup for GVN
on 40.gcc.

llvm-svn: 122819

llvm-svn: 122817

llvm-svn: 122815

ashr's with huge shift amounts, PR8896

llvm-svn: 122814

makes getLeader() nonrecursive.

llvm-svn: 122811

llvm-svn: 122809

when safe.

The testcase is basically this nested loop:
void foo(char *X) {
  for (int i = 0; i != 100; ++i) 
    for (int j = 0; j != 100; ++j)
      X[j+i*100] = 0;
}

which gets turned into a single memset now.  clang -O3 doesn't optimize
this yet though due to a phase ordering issue I haven't analyzed yet.

llvm-svn: 122806

instruction *after* the store.  The store will always be deleted
if the transformation kicks in, so we'd do an N^2 scan of every
loop block.  Whoops.

llvm-svn: 122805

spent in StrongPHIElimination on 403.gcc.

llvm-svn: 122803

CodeGenPrepare (which is the default behavior).

llvm-svn: 122801

llvm-svn: 122795

llvm-svn: 122794

FunctionPass. It probably doesn't have a reason to be a LoopPass, as it will
probably drop the simple fixed point and either use RPO iteration or Duncan's
approach in instsimplify of only revisiting instructions that have changed.

The next step is to preserve LoopSimplify. This looks like it won't be too hard,
although the pass manager doesn't actually seem to respect when non-loop passes
claim to preserve LCSSA or LoopSimplify. This will have to be fixed.

llvm-svn: 122791

stop setting NSW: signed overflow is possible.  Thanks to Dan
for pointing these out.

llvm-svn: 122790

llvm-svn: 122789

llvm-svn: 122788

Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,
have GlobalsModRef handle this conservatively by simply removing the value from its maps.

llvm-svn: 122787

invalidated by stores, so they can be handled as 'simple'
operations.

llvm-svn: 122785

prologue and epilogue if the adjustment is 8. Similarly, use pushl / popl if
the adjustment is 4 in 32-bit mode.

In the epilogue, takes care to pop to a caller-saved register that's not live
at the exit (either return or tailcall instruction).
rdar://8771137

llvm-svn: 122783

llvm-svn: 122778

a pointer value has potentially become escaping.  Implementations can choose to either fall back to
conservative responses for that value, or may recompute their analysis to accomodate the change.

llvm-svn: 122777

exposed.  It turns out to be a latent bug in basicaa, scary.

llvm-svn: 122772

almost-but-not-quite-identical code.  No intended functionality change.

llvm-svn: 122760

that are allowed to have metadata operands are intrinsic calls,
and the only ones that take metadata currently return void.
Just reject all void instructions, which should not be value
numbered anyway.  To future proof things, add an assert to the
getHashValue impl for calls to check that metadata operands 
aren't present.

llvm-svn: 122759

nested values, so they can change and drop to null, which can
change the hash and cause havok.

It turns out that it isn't a good idea to value number stuff
with metadata operands anyway, so... don't.

llvm-svn: 122758

InstructionSimplify on instructions that didn't change since the
last time round the loop.

llvm-svn: 122745

capacity on the Visited SmallPtrSet. On 403.gcc, this is about a 4.5% speedup of
CodeGenPrepare time (which itself is 10% of time spent in the backend).

This is progress towards PR8889.

llvm-svn: 122741

elimination as well.  This deletes 60 stores in 176.gcc
that largely come from bitfield code.

llvm-svn: 122736

a 28% speedup of MachineCSE time on 403.gcc.

llvm-svn: 122735

speeding earlycse up by 6%.

llvm-svn: 122733

store->load forwarding.  This allows EarlyCSE to zap 600 more
loads from 176.gcc.

llvm-svn: 122732

by their pointer instead of using MemoryValue to wrap it.

llvm-svn: 122731