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

This handles the case in which LSR rewrites an IV user that is a phi and
splits critical edges originating from a switch.
Fixes <rdar://problem/6453893> LSR is not splitting edges "nicely"

llvm-svn: 141059

We want heuristics to be based on accurate data, but more importantly
we don't want llvm to behave randomly. A benign trunc inserted by an
upstream pass should not cause a wild swings in optimization
level. See PR11034. It's a general problem with threshold-based
heuristics, but we can make it less bad.

llvm-svn: 140919

llvm-svn: 140821

handle the case where the retain is in a different basic block.
rdar://10210274.

llvm-svn: 140815

objc_retainBlock call is potentially responsible for copying
the block to the heap to extend its lifetime. rdar://10209613.

llvm-svn: 140814

llvm-svn: 140769

Rewriting the entire loop nest now requires -enable-lsr-nested.
See PR11035 for some performance data.
A few unit tests specifically test nested LSR, and are now under a flag.

llvm-svn: 140762

llvm-svn: 140670

Stop emitting instructions with the name "tmp" they eat up memory and have to be uniqued, without any benefit.

If someone prefers %tmp42 to %42, run instnamer.

llvm-svn: 140634

split landingpad instructions into a PHI node.
PR11016

llvm-svn: 140592

Disabling aggressive LSR saves compilation time, and with the new
indvars behavior usually improves performance.

llvm-svn: 140590

llvm-svn: 140583

The minor bug heuristic was noticed by inspection. I added the
isLoser/isValid helpers because they will become more
important with subsequent checkins.

llvm-svn: 140580

No test case. Noticed by inspection and I doubt it ever affects the
outcome of the overall heuristic, let alone final codegen.

llvm-svn: 140431

llvm-svn: 140327

Make sure IPSCCP never marks a tracked call as overdefined in SCCPSolver::ResolvedUndefsIn.  If we do, we can end up in a situation where a function is resolved to return a constant, but the caller is marked overdefined, which confuses the code later.

<rdar://problem/9956541> (again).

llvm-svn: 140210

llvm-svn: 139842

which could theoretically throw.

llvm-svn: 139710

in memory relevant to the optimizer. rdar://10050579.

llvm-svn: 139708

llvm-svn: 139583

llvm-svn: 139579

llvm-svn: 139574

llvm-svn: 139571

llvm-svn: 139565

No tests; these changes aren't really interesting in the sense that the logic is the same for volatile and atomic.

I believe this completes all of the changes necessary for the optimizer to handle loads and stores correctly.  I'm going to try and come up with some additional testing, though.

llvm-svn: 139533

llvm-svn: 139517