Use isNegative (NFC)

Author: kazutakahirata

llvm/include/llvm/CodeGen/BasicTTIImpl.h

@@ -1514,7 +1514,7 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
           InstructionCost Cost = (ActiveBits + PopCount - 2) *
                                  thisT()->getArithmeticInstrCost(
                                      Instruction::FMul, RetTy, CostKind);
-          if (RHSC->getSExtValue() < 0)
+          if (RHSC->isNegative())
             Cost += thisT()->getArithmeticInstrCost(Instruction::FDiv, RetTy,
                                                     CostKind);
           return Cost;

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -1305,7 +1305,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
   // not a multiple of element size then behavior is undefined.
   if (auto *AMI = dyn_cast<AtomicMemIntrinsic>(II))
     if (ConstantInt *NumBytes = dyn_cast<ConstantInt>(AMI->getLength()))
-      if (NumBytes->getSExtValue() < 0 ||
+      if (NumBytes->isNegative() ||
           (NumBytes->getZExtValue() % AMI->getElementSizeInBytes() != 0)) {
         CreateNonTerminatorUnreachable(AMI);
         assert(AMI->getType()->isVoidTy() &&

mlir/lib/Dialect/Affine/IR/AffineOps.cpp

@@ -2026,7 +2026,7 @@ ParseResult AffineForOp::parse(OpAsmParser &parser, OperationState &result) {
                               result.attributes))
       return failure();
 
-    if (stepAttr.getValue().getSExtValue() < 0)
+    if (stepAttr.getValue().isNegative())
       return parser.emitError(
           stepLoc,
           "expected step to be representable as a positive signed integer");