llvm-svn: 112620

More Chris-inspired JumpThreading fixes: use ConstantExpr to correctly constant-fold undef, and be more careful with its return value.
This actually exposed an infinite recursion bug in ComputeValueKnownInPredecessors which theoretically already existed (in JumpThreading's
handling of and/or of i1's), but never manifested before.  This patch adds a tracking set to prevent this case.

llvm-svn: 112589

Re-apply r112539, being more careful to respect the return values of the constant folding methods.  Additionally,
use the ConstantExpr::get*() methods to simplify some constant folding.

llvm-svn: 112550

llvm-svn: 112543

Fixes and cleanups pointed out by Chris.  In general, be careful to handle 0 results from ComputeValueKnownInPredecessors
(indicating undef), and re-use existing constant folding APIs.

llvm-svn: 112539

llvm-svn: 112286

Use LVI to eliminate conditional branches where we've tested a related condition previously.  Update tests for this change.
This fixes PR5652.

llvm-svn: 112270

llvm-svn: 112198

llvm-svn: 111923

llvm-svn: 111834

llvm-svn: 111816

llvm-svn: 111551

llvm-svn: 111543

llvm-svn: 111382

from the LHS should disable reconsidering that pred on the
RHS.  However, knowing something about the pred on the RHS
shouldn't disable subsequent additions on the RHS from
happening.

llvm-svn: 111349

llvm-svn: 110460

llvm-svn: 110410

ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396

llvm-svn: 110384

llvm-svn: 109424

llvm-svn: 109045

llvm-svn: 108142

the LHS and RHS of an and/or instruction, don't multiply add
known predecessor values.  This fixes the crash on testcase
from PR7498

llvm-svn: 108114

fixes PR7356.

llvm-svn: 105950

lib/Transforms/Utils and into lib/Analysis so that Analysis passes
can use them.

llvm-svn: 104949

in some cases.

llvm-svn: 100937

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

instead of considering x|undef -> x, which may not be true.

llvm-svn: 95850

for arbitrary terminators in predecessors, don't assume
it is a conditional or uncond branch.  The testcase shows
an example where they can happen with switches.

llvm-svn: 94323

handle the case when we can infer an input to the xor
from all inputs that agree, instead of going into an
infinite loop.  Another part of PR6199

llvm-svn: 94321

llvm-svn: 94319

in JT.

2) When cloning blocks for PHI or xor conditions, use
instsimplify to simplify the code as we go.  This allows us to 
squish common cases early in JT which opens up opportunities for
subsequent iterations, and allows it to completely simplify the
testcase.

llvm-svn: 93253

llvm-svn: 93222

condition is a xor with a phi node.  This eliminates nonsense
like this from 176.gcc in several places:

 LBB166_84:
        testl   %eax, %eax
-       setne   %al
-       xorb    %cl, %al
-       notb    %al
-       testb   $1, %al
-       je      LBB166_85
+       je      LBB166_69
+       jmp     LBB166_85

This is rdar://7391699

llvm-svn: 93221

on branches by renaming it and checking for a branch at the call site.

llvm-svn: 93208

llvm-svn: 92912

llvm-svn: 92614

llvm-svn: 92211

llvm-svn: 90708