- Eliminate redundant successors.
 - Convert an indirectbr with one successor into a direct branch.

Also, generalize SimplifyCFG to be able to be run on a function entry block.
It knows quite a few simplifications which are applicable to the entry
block, and it only needs a few checks to avoid trouble with the entry block.

llvm-svn: 111060

llvm-svn: 109098

llvm-svn: 108427

"bonus" instruction to be speculatively executed.  Add a heuristic to
ensure we're not tripping up out-of-order execution by checking that this bonus
instruction only uses values that were already guaranteed to be available.

This allows us to eliminate the short circuit in (x&1)&&(x&2).

llvm-svn: 108351

llvm-svn: 108133

llvm-svn: 107974

llvm-svn: 99917

spotted by baldrick -- thanks\!

llvm-svn: 99914

llvm-svn: 98490

and T->isPointerTy().  Convert most instances of the first form to the second form.
Requested by Chris.

llvm-svn: 96344

isInteger, we now have isFloatTy and isIntegerTy.  Requested by Chris!

llvm-svn: 96223

Weird code sometimes uses pointer constants other than null. This patch
teaches SimplifyCFG to build switch instructions in those cases.

Code like this:

void f(const char *x) {
  if (!x)
    puts("null");
  else if ((uintptr_t)x == 1)
    puts("one");
  else if (x == (char*)2 || x == (char*)3)
    puts("two");
  else if ((intptr_t)x == 4)
    puts("four");
  else
    puts(x);
}

Now becomes a switch:

define void @f(i8* %x) nounwind ssp {
entry:
  %magicptr23 = ptrtoint i8* %x to i64            ; <i64> [#uses=1]
  switch i64 %magicptr23, label %if.else16 [
    i64 0, label %if.then
    i64 1, label %if.then2
    i64 2, label %if.then9
    i64 3, label %if.then9
    i64 4, label %if.then14
  ]

Note that LLVM's own DenseMap uses magic pointers.

llvm-svn: 95439

llvm-svn: 92760

Avoid going through the LLVMContext for type equality where it's safe to dereference the type pointer.

llvm-svn: 92726

llvm-svn: 92604

 Intrinsic::dbg_stoppoint
 Intrinsic::dbg_region_start 
 Intrinsic::dbg_region_end 
 Intrinsic::dbg_func_start
AutoUpgrade simply ignores these intrinsics now.

llvm-svn: 92557

llvm-svn: 90324

llvm-svn: 89297

llvm-svn: 86666

from various APIs, addressing PR5325.

llvm-svn: 86231

llvm-svn: 85635

This reduces codesize on a variety of codes by 1-2% on x86-64. It also
helps clean up after SSAUpdater.

llvm-svn: 85626

this will increase the likelihood of common code getting sunk towards
the unwind.

llvm-svn: 83996

update all the callers.

llvm-svn: 82889

and introduce a new Instruction::isIdenticalTo which tests for full
identity, including the SubclassOptionalData flags. Also, fix the
Instruction::clone implementations to preserve the SubclassOptionalData
flags. Finally, teach several optimizations how to handle
SubclassOptionalData correctly, given these changes.

This fixes the counterintuitive behavior of isIdenticalTo not comparing
the full value, and clone not returning an identical clone, as well as
some subtle bugs that could be caused by these.

Thanks to Nick Lewycky for reporting this, and for an initial patch!

llvm-svn: 80038

llvm-svn: 79849

This required converting a bunch of stuff off DOUT and other cleanups.

llvm-svn: 79819

unfoldable references to a PHI node in the block being folded, and disable
the transformation in that case.  The correct transformation of such PHI
nodes depends on whether BB dominates Succ, and dominance is expensive 
to compute here.  (Alternatively, it's possible to check whether any 
uses are live, but that's also essentially a dominance calculation. 
Another alternative is to use reg2mem, but it probably isn't a good idea to
use that in simplifycfg.)

Also, remove some incorrect code from CanPropagatePredecessorsForPHIs 
which is made unnecessary with this patch: it didn't consider the case 
where a PHI node in BB has multiple uses.

llvm-svn: 79174

llvm-svn: 78948

llvm-svn: 78809

llvm-svn: 77635

llvm-svn: 77152

 - Some clients which used DOUT have moved to DEBUG. We are deprecating the
   "magic" DOUT behavior which avoided calling printing functions when the
   statement was disabled. In addition to being unnecessary magic, it had the
   downside of leaving code in -Asserts builds, and of hiding potentially
   unnecessary computations.

llvm-svn: 77019

Revert the ConstantInt constructors back to their 2.5 forms where possible, thanks to contexts-on-types.  More to come.

llvm-svn: 77011

llvm-svn: 76702

isSafeToSpeculativelyExecute. The new method is a bit closer to what 
the callers actually care about in that it rejects more things callers 
don't want.  It also adds more precise handling for integer 
division, and unifies code for analyzing the legality of a speculative 
load.

llvm-svn: 76150

llvm-svn: 75497

This started as a small change, I swear.  Unfortunately, lots of things call the [I|F]CmpInst constructors.  Who knew!?

llvm-svn: 75200

llvm-svn: 74878

llvm-svn: 74844