llvm-svn: 121669

location in simplifycfg.  In the old days, SimplifyCFG was never run on
the entry block, so we had to scan over all preds of the BB passed into
simplifycfg to do this xform, now we can just check blocks ending with
a condbranch.  This avoids a scan over all preds of every simplified 
block, which should be a significant compile-time perf win on functions
with lots of edges.  No functionality change.

llvm-svn: 121668

llvm-svn: 121667

llvm-svn: 121664

(x & 2^n) ? 2^m+C : C

we can offset both arms by C to get the "(x & 2^n) ? 2^m : 0" form, optimize the
select to a shift and apply the offset afterwards.

llvm-svn: 121609

to catch cases where n != m with a shift.

llvm-svn: 121608

llvm-svn: 121362

substitution because it doesn't actually change the IR.  Patch by
Jakub Staszak!

llvm-svn: 121361

before eliminating the operation that zeros them. This fixes rdar://8739316.

llvm-svn: 121353

The last uses of these functions were removed in r113852 when LazyValueInfo was permanently enabled and removed the need for them.

llvm-svn: 121133

zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.

llvm-svn: 121120

(if available) as we go so that we get simple constantexprs not insane ones.
This fixes the failure of clang/test/CodeGenCXX/virtual-base-ctor.cpp
that the previous iteration of this patch had.

llvm-svn: 121111

CodeGenCXX/virtual-base-ctor.cpp.

llvm-svn: 121102

put in a global variable's initializer.

llvm-svn: 121100

Implement jump threading of 'indirectbr' by keeping track of whether we're looking for ConstantInt*s or BlockAddress*s.

llvm-svn: 121066

No functionality change.

llvm-svn: 121042

llvm-svn: 121040

llvm-svn: 121038

optimization.

Consider:
static void foo() {
  A = alloca
  ...
}

static void bar() {
  B = alloca
  ...
  call foo();
}

void main() {
  bar()
}

The inliner proceeds bottom up, but lets pretend it decides not to inline foo
into bar.  When it gets to main, it inlines bar into main(), and says "hey, I
just inlined an alloca "B" into main, lets remember that.  Then it keeps going
and finds that it now contains a call to foo.  It decides to inline foo into
main, and says "hey, foo has an alloca A, and I have an alloca B from another
inlined call site, lets reuse it".  The problem with this of course, is that 
the lifetime of A and B are nested, not disjoint.

Unfortunately I can't create a reasonable testcase for this: the one in the
PR is both huge and extremely sensitive, because you minor tweaks end up
causing foo to get inlined into bar too early.  We already have tests for the
basic alloca merging optimization and this does not break them.

llvm-svn: 120995

llvm-svn: 120994

llvm-svn: 120993

memcpy's like:
  memcpy(A, B)
  memcpy(A, C)

we cannot delete the first memcpy as dead if A and C might be aliases.
If so, we actually get:

  memcpy(A, B)
  memcpy(A, A)

which is not correct to transform into:

  memcpy(A, A)

This patch was heavily influenced by Jakub Staszak's patch in PR8728, thanks
Jakub!

llvm-svn: 120974

Should have no functional change other than the order of two transformations that are mutually-exclusive and the exact formatting of debug output.
Internally, it now stores the ConstantInt*s as Constant*s, and actual undef values instead of nulls.

llvm-svn: 120946

llvm-svn: 120945

  (indirectbr (select cond, blockaddress(@fn, BlockA),
                            blockaddress(@fn, BlockB)))
into
  (br cond, BlockA, BlockB).

llvm-svn: 120943

setAllBits(), setBit(unsigned), etc.

llvm-svn: 120564

20040709-1.c from the gcc testsuite.  I was using the size of a
pointer instead of the pointee.  This fixes rdar://8713376

llvm-svn: 120519

llvm-svn: 120498

may-aliasing stores that partially overlap with different base
pointers.  This implements PR6043 and the non-variable part of
PR8657

llvm-svn: 120485

llvm-svn: 120476

llvm-svn: 120474

llvm-svn: 120471

the code.  We now get accurate sizes on Loads, though it surely doesn't
matter in practice.

llvm-svn: 120469

1. if the underlying pointer passed in can be resolved
   to any argument or alloca, then we don't need to scan.
   Previously we would only avoid the scan if the alloca
   or byval was actually considered dead.
2. The dead store processing code is itself completely
   dead and didn't handle volatile stores right anyway,
   so delete it.  This allows simplifying the interface
   to RemoveAccessedObjects.

llvm-svn: 120467

made sense to me.  We now have a set of dead stack objects, and
they become live when loaded.  Fix a theoretical problem where
we'd pass in the wrong pointer to the alias query.

llvm-svn: 120465

If the call might read all the allocas, stop scanning early.
Convert a vector to smallvector, shrink SmallPtrSet to 16 instead
of 64 to avoid crazy linear scans.

llvm-svn: 120463

there should be a better way to do this.  PR 8679.

llvm-svn: 120457

llvm-svn: 120454

AA and MD pass info instead of using getAnalysis<> all over.

llvm-svn: 120453

llvm-svn: 120452