Move Instruction::isSafeToSpeculativelyExecute out of VMCore and

into Analysis as a standalone function, since there's no need for
it to be in VMCore. Also, update it to use isKnownNonZero and
other goodies available in Analysis, making it more precise,
enabling more aggressive optimization.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146610 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 53 deletions

diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index 73191c1965..8c8fbf9acd 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -391,59 +391,6 @@ bool Instruction::isCommutative(unsigned op) {
   }
 }
 
-bool Instruction::isSafeToSpeculativelyExecute() const {
-  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
-    if (Constant *C = dyn_cast<Constant>(getOperand(i)))
-      if (C->canTrap())
-        return false;
-
-  switch (getOpcode()) {
-  default:
-    return true;
-  case UDiv:
-  case URem: {
-    // x / y is undefined if y == 0, but calcuations like x / 3 are safe.
-    ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1));
-    return Op && !Op->isNullValue();
-  }
-  case SDiv:
-  case SRem: {
-    // x / y is undefined if y == 0, and might be undefined if y == -1,
-    // but calcuations like x / 3 are safe.
-    ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1));
-    return Op && !Op->isNullValue() && !Op->isAllOnesValue();
-  }
-  case Load: {
-    const LoadInst *LI = cast<LoadInst>(this);
-    if (!LI->isUnordered())
-      return false;
-    return LI->getPointerOperand()->isDereferenceablePointer();
-  }
-  case Call:
-    return false; // The called function could have undefined behavior or
-                  // side-effects.
-                  // FIXME: We should special-case some intrinsics (bswap,
-                  // overflow-checking arithmetic, etc.)
-  case VAArg:
-  case Alloca:
-  case Invoke:
-  case PHI:
-  case Store:
-  case Ret:
-  case Br:
-  case IndirectBr:
-  case Switch:
-  case Unwind:
-  case Unreachable:
-  case Fence:
-  case LandingPad:
-  case AtomicRMW:
-  case AtomicCmpXchg:
-  case Resume:
-    return false; // Misc instructions which have effects
-  }
-}
-
 Instruction *Instruction::clone() const {
   Instruction *New = clone_impl();
   New->SubclassOptionalData = SubclassOptionalData;