[AssumptionCache] Remove unnecessary bitcast/not handling

We only handle not for the top level value of the condition, so
move it there instead of trying to look through not at all leafs.
Also remove bitcast handling entirely -- we don't do anything
special wrt bitcasts, this is probably a leftover from pointer
types.

Author: nikic

llvm/lib/Analysis/AssumptionCache.cpp

@@ -69,8 +69,7 @@ findAffectedValues(CallBase *CI, TargetTransformInfo *TTI,
 
       // Peek through unary operators to find the source of the condition.
       Value *Op;
-      if (match(I, m_BitCast(m_Value(Op))) ||
-          match(I, m_PtrToInt(m_Value(Op))) || match(I, m_Not(m_Value(Op)))) {
+      if (match(I, m_PtrToInt(m_Value(Op)))) {
         if (isa<Instruction>(Op) || isa<Argument>(Op))
           Affected.push_back({Op, Idx});
       }
@@ -85,6 +84,8 @@ findAffectedValues(CallBase *CI, TargetTransformInfo *TTI,
 
   Value *Cond = CI->getArgOperand(0), *A, *B;
   AddAffected(Cond);
+  if (match(Cond, m_Not(m_Value(A))))
+    AddAffected(A);
 
   CmpInst::Predicate Pred;
   if (match(Cond, m_Cmp(Pred, m_Value(A), m_Value(B)))) {