}
		throw("fault")
	case _SIGTRAP:
		if gp.paniconfault {
			panicmem()
		}
		throw(note)
	case _SIGINTDIV:
		panicdivide()
	case _SIGFLOAT:
		panicfloat()
	default:
		panic(errorString(note))
	}
}

// indexNoFloat is bytealg.IndexString but safe to use in a note
// handler.
func indexNoFloat(s, t string) int {
	if len(t) == 0 {
		return 0

		panicoverflow()
	case _EXCEPTION_FLT_DENORMAL_OPERAND,
		_EXCEPTION_FLT_DIVIDE_BY_ZERO,
		_EXCEPTION_FLT_INEXACT_RESULT,
		_EXCEPTION_FLT_OVERFLOW,
		_EXCEPTION_FLT_UNDERFLOW:
		panicfloat()
	}
	throw("fault")
}

// Following are not implemented.

func initsig(preinit bool) {
}

func sigenable(sig uint32) {
}

func sigdisable(sig uint32) {
}

// code generated by the compiler for out of bounds index expressions,
// out of bounds slice expressions, division by zero, and shift by negative.
// The panicdivide (again), panicoverflow, panicfloat, and panicmem
// functions are called by the signal handler when a signal occurs
// indicating the respective problem.
//
// Since panic{Index,Slice,shift} are never called directly, and

		}
		throw("fault")
	case _SIGFPE:
		switch gp.sigcode0 {
		case _FPE_INTDIV:
			panicdivide()
		case _FPE_INTOVF:
			panicoverflow()
		}
		panicfloat()
	}

	if gp.sig >= uint32(len(sigtable)) {
		// can't happen: we looked up gp.sig in sigtable to decide to call sigpanic
		throw("unexpected signal value")
	}
	panic(errorString(sigtable[gp.sig].name))

using ops::Div;
using ops::MatMul;
using ops::Placeholder;
using ops::Real;
using ops::Split;
using ops::Square;
using ops::Stack;
using ops::Sub;
using ops::Unstack;

TEST(GradientCheckerTest, BasicFloat) {
  Scope scope = Scope::NewRootScope();
  TensorShape shape({2, 4, 3});
  auto x = Placeholder(scope, DT_FLOAT, Placeholder::Shape(shape));
  auto y = Square(scope, x);
  float max_error;