Get rid of an optimization in SCCP which appears to have many issues.  Specifically, it doesn't handle many cases involving undef correctly, and it is missing other checks which
lead to it trying to re-mark a value marked as a constant with a different value.  It also appears to trigger very rarely.

Fixes PR11357.

llvm-svn: 144352

Size of data being pointed to wasn't always being checked so some small writes were killing big writes

Fixes <rdar://problem/10426753>

llvm-svn: 144312

Currently checks alignment and killing stores on a power of 2 boundary as this is likely
to trim the size of the earlier store without breaking large vector stores into scalar ones.

Fixes <rdar://problem/10140300>

llvm-svn: 144239

LICM pass now understands invariant load metadata.  Nothing generates this yet so it will currently never get used in real tests

llvm-svn: 144107

llvm-svn: 143808

the end of it is dead.", which appears to break bootstrapping LLVM.

llvm-svn: 143668

llvm-svn: 143634

Only currently done if the later store is writing to a power of 2 address or 
has the same alignment as the earlier store as then its likely to not break up
large stores into smaller ones

Fixes <rdar://problem/10140300>

llvm-svn: 143630

We've been hitting asserts in this code due to the many supported
combintions of modes (iv-rewrite/no-iv-rewrite) and IV types. This
second rewrite of the code attempts to deal with these cases systematically.

llvm-svn: 143546

silence -Wparentheses.

llvm-svn: 143534

Narrowest possible fix for PR11279.

llvm-svn: 143522

SimplifyLibCalls: Use IRBuilder.CreateGlobalString when creating a string for printf->puts, which correctly sets the unnamed_addr bit on the resulting GlobalVariable.

Fixes PR11264.

llvm-svn: 143289

Fixes rdar://10359193 Indvar LinearFunctionTestReplace assertion

llvm-svn: 143183

It is not safe to sink an alloca into a stacksave/stackrestore pair, so don't do that. <rdar://problem/10352360>

llvm-svn: 143093

element types, even though the element extraction code does. It is surprising
that this bug has been here for so long. Fixes <rdar://problem/10318778>.

llvm-svn: 142740

elimination on them too.

llvm-svn: 142735

Patch by Pranav Bhandarkar!

llvm-svn: 142556

tag on objc_retainBlock calls, which indicates that they may be
optimized away. rdar://10211286.

llvm-svn: 142298

possibility that it will span multiple CFG diamonds/triangles which
could have different controlling predicates.  rdar://10282956

llvm-svn: 142222

Some code want to check that *any* call within a function has the 'returns
twice' attribute, not just that the current function has one.

llvm-svn: 142221

obsolete. Check the attribute instead.
<rdar://problem/8031714>

llvm-svn: 142212

llvm-svn: 142204

There is no reason to have simple IR level pass in lib/Target.

llvm-svn: 142200

on the memcpy call will pull up other unrelated stuff. Fixes PR11142.

llvm-svn: 142150

use can't be dominated, saving one domtree lookup.

llvm-svn: 142066

I rewrote the algorithm a while back so it doesn't require map lookup,
but neglected to change the data structure. This was caught by
llvm-gcc self host, not because there's anything special about
llvm-gcc, but because it is the only test for nondeterminism we
currently have. Unit tests don't work well for everything; we should
always try to have a nondeterminism stress test running.

Fixes PR11133: llvm-gcc self host .o mismatch after enable-iv-rewrite=false

llvm-svn: 142036

Someone more familiar with LSR should double-check that the extra cast is actually doing the right thing in the overflow cases; I'm not completely confident that's that case. 

llvm-svn: 141916

Enhance the memdep interface so that users can tell the difference between a dependency which cannot be calculated and a path reaching the entry point of the function. This patch introduces isNonFuncLocal, which replaces isUnknown in some cases.

Patch by Xiaoyi Guo.

llvm-svn: 141896

Fix a couple hash functions so that they do not depend on undefined shifts.  Based on patch by Ahmed Charles.

llvm-svn: 141820

llvm-svn: 141750

would have never worked, since the element type of a vector type is never a
vector type. Also fix the conditional to be more direct in checking whether
EltTy is a vector type.

llvm-svn: 141713

lowering of NEON code. It provides little-to-no benefit now and only introduces
additional complexity.

llvm-svn: 141646

I'm not sure we will need it in the long run, but the option is
currently useful for checking if the output of LSR is "clean".

llvm-svn: 141634

IVs.

Indvars previously chose randomly between congruent IVs. Now it will
bias the decision toward IVs that SCEVExpander likes to create. This
was not done to fix any problem, it's just a welcome side effect of
factoring code.

llvm-svn: 141633

Fixes rdar://problem/5064068

llvm-svn: 141442

  switch (n) {
    case 27:
      do_something(x);
    ...
  }
the call do_something(x) will be replaced with do_something(27).  In
gcc-as-one-big-file this results in the removal of about 500 lines of
bitcode (about 0.02%), so has about 1/10 of the effect of propagating
branch conditions.

llvm-svn: 141360

llvm-svn: 141333

While I'm here, fix the related issue with strncmp, add some actual tests for strcmp and strncmp, and start using StringRef::compare for constant folding instead of using strcmp/strncmp so that the optimized IR isn't dependent on the host's implementation of strcmp.

llvm-svn: 141227

branch "br i1 %x, label %if_true, label %if_false" then it replaces
"%x" with "true" in places only reachable via the %if_true arm, and
with "false" in places only reachable via the %if_false arm.  Except
that actually it doesn't: if value numbering shows that %y is equal
to %x then, yes, %y will be turned into true/false in this way, but
any occurrences of %x itself are not transformed.  Fix this.  What's
more, it's often the case that %x is an equality comparison such as
"%x = icmp eq %A, 0", in which case every occurrence of %A that is
only reachable via the %if_true arm can be replaced with 0.  Implement
this and a few other variations on this theme.  This reduces the number
of lines of LLVM IR in "GCC as one big file" by 0.2%.  It has a bigger
impact on Ada code, typically reducing the number of lines of bitcode
by around 0.4% by removing repeated compiler generated checks.  Passes
the LLVM nightly testsuite and the Ada ACATS testsuite.

llvm-svn: 141177

it's OK for the false/true destination to have multiple
predecessors as long as the extra ones are dominated by
the branch destination.

llvm-svn: 141176