refusing to optimize two memcpy's like this:

copy A <- B
copy C <- A

if it couldn't prove that noalias(B,C).  We can eliminate
the copy by producing a memmove instead of memcpy.

llvm-svn: 119694

source and dest are known to not overlap.

llvm-svn: 119692

there is no need to check to see if the source and dest of a memcpy are noalias,
behavior is undefined if not.

llvm-svn: 119691

llvm-svn: 119690

out of processMemCpy into its own function.

llvm-svn: 119687

if it is passed as a byval argument.  The byval argument will just be a
read, so it is safe to read from the original global instead.  This allows
us to promote away the %agg.tmp alloca in PR8582

llvm-svn: 119686

to ignore calls that obviously can't modify the alloca
because they are readonly/readnone.

llvm-svn: 119683

optimization.  If the alloca that is "memcpy'd from constant" also has
a memcpy from *it*, ignore it: it is a load.  We now optimize the testcase to:

define void @test2() {
  %B = alloca %T
  %a = bitcast %T* @G to i8*
  %b = bitcast %T* %B to i8*
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %b, i8* %a, i64 124, i32 4, i1 false)
  call void @bar(i8* %b)
  ret void
}

previously we would generate:

define void @test() {
  %B = alloca %T
  %b = bitcast %T* %B to i8*
  %G.0 = getelementptr inbounds %T* @G, i32 0, i32 0
  %tmp3 = load i8* %G.0, align 4
  %G.1 = getelementptr inbounds %T* @G, i32 0, i32 1
  %G.15 = bitcast [123 x i8]* %G.1 to i8*
  %1 = bitcast [123 x i8]* %G.1 to i984*
  %srcval = load i984* %1, align 1
  %B.0 = getelementptr inbounds %T* %B, i32 0, i32 0
  store i8 %tmp3, i8* %B.0, align 4
  %B.1 = getelementptr inbounds %T* %B, i32 0, i32 1
  %B.12 = bitcast [123 x i8]* %B.1 to i8*
  %2 = bitcast [123 x i8]* %B.1 to i984*
  store i984 %srcval, i984* %2, align 1
  call void @bar(i8* %b)
  ret void
}

llvm-svn: 119682

llvm-svn: 119570

functions of ScalarEvolution, in preparation for memoization and
other optimizations.

llvm-svn: 119562

to avoid an unneeded dependence.

llvm-svn: 119557

systematically, CollapsePhi will always return null here.  Note
that CollapsePhi did an extra check, isSafeReplacement, which
the SimplifyInstruction logic does not do.  I think that check
was bogus - I guess we will soon find out!  (It was originally
added in commit 41998 without a testcase).

llvm-svn: 119456

rather than calling hasConstantValue.  No intended functionality change.

llvm-svn: 119352

it to get better phi node simplification.

llvm-svn: 119055

"%z = %x and %y".  If GVN can prove that %y equals %x, then it turns
this into "%z = %x and %x".  With the new code, %z will be replaced
with %x everywhere (and then deleted).  Previously %z would be value
numbered too, which is a waste of time.  Also, while a clever value
numbering algorithm would give %z the same value number as %x, our
current one doesn't do so (at least I don't think it does).  The new
logic has an essentially equivalent effect to what you would get if
%z was given the same value number as %x, i.e. it should make value
numbering smarter.  While there, get hold of target data once at the
start rather than a gazillion times all over the place.

llvm-svn: 118923

one store dead. This is especially noticeable in
SingleSource/Benchmarks/Shootout/objinst.

llvm-svn: 118875

and vaarg instructions.

llvm-svn: 118845

llvm-svn: 118788

execute. Make Sink's predicate more precise.

llvm-svn: 118787

references. For example, this allows gvn to eliminate the load in
this example:

  void foo(int n, int* p, int *q) {
    p[0] = 0;
    p[1] = 1;
    if (n) {
      *q = p[0];
    }
  }

llvm-svn: 118714

instructions instead of hard-coding operand numbers.

llvm-svn: 118698

llvm-svn: 118618

Give up on doing in-line instruction simplification during correlated value propagation.  Instruction simplification
needs to be guaranteed never to be run on an unreachable block.  However, earlier block simplifications may have
changed the CFG to make block that were reachable when we began our iteration unreachable by the time we try to
simplify them. (Note that this also means that our depth-first iterators were potentially being invalidated).

This should not have a large impact on code quality, since later runs of instcombine should pick up these simplifications.
Fixes PR8506.

llvm-svn: 117709

Inline asm multiple alternative constraints development phase 2 - improved basic logic, added initial platform support.

llvm-svn: 117667

uint64_t, plus fixes for places I missed before.

llvm-svn: 116875

llvm-svn: 116858

they do not also require them.  This allows us to reduce inter-pass linkage
dependencies.

llvm-svn: 116854

use uint64_t.

llvm-svn: 116839

Get rid of static constructors for pass registration.  Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.

llvm-svn: 116820

llvm-svn: 116815

llvm-svn: 116743

llvm-svn: 116670

forwarding is implemented with a load/store pair rather than a memcpy.

llvm-svn: 116637

llvm-svn: 116387

perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.

llvm-svn: 116334

formulae which become illegal as a result of the offset updating don't
escape.

This is for rdar://8529692. No testcase yet, because the given cases
hit use-list ordering differences.

llvm-svn: 116093

llvm-svn: 116034

one user. This code will be restructured soon and FormulaSorter
is getting in the way.

llvm-svn: 116012

llvm-svn: 116011

not just base registers.

llvm-svn: 116010