[SCCP] Remove code in visitBinaryOperator (and add tests).

We visit and/or, we try to derive a lattice value for the
instruction even if one of the operands is overdefined.
If the non-overdefined value is still 'unknown' just return and wait
for ResolvedUndefsIn to "plug in" the correct value. This simplifies
the logic a bit. While I'm here add tests for missing cases.

llvm-svn: 287709

1 files changed, 3 insertions, 11 deletions

diff --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index eeb36bb56a1..9de3059dadf 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -928,25 +928,17 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
       NonOverdefVal = &V2State;
 
     if (NonOverdefVal) {
-      if (NonOverdefVal->isUnknown()) {
-        // Could annihilate value.
-        if (I.getOpcode() == Instruction::And)
-          markConstant(IV, &I, Constant::getNullValue(I.getType()));
-        else if (VectorType *PT = dyn_cast<VectorType>(I.getType()))
-          markConstant(IV, &I, Constant::getAllOnesValue(PT));
-        else
-          markConstant(IV, &I,
-                       Constant::getAllOnesValue(I.getType()));
+      if (NonOverdefVal->isUnknown())
         return;
-      }
 
       if (I.getOpcode() == Instruction::And) {
         // X and 0 = 0
         if (NonOverdefVal->getConstant()->isNullValue())
           return markConstant(IV, &I, NonOverdefVal->getConstant());
       } else {
+        // X or -1 = -1
         if (ConstantInt *CI = NonOverdefVal->getConstantInt())
-          if (CI->isAllOnesValue())     // X or -1 = -1
+          if (CI->isAllOnesValue())
             return markConstant(IV, &I, NonOverdefVal->getConstant());
       }
     }